I think that all this proves is that you should own a PPFD meter as the choices you make in scape, type of tank, painted or not, how often the glass is cleaned, lighting and their settings/mounting, water filtration method (turbidity), flow (microbubbles) and so on make it almost impossible to determine exactly what PPFD a tank will have. However I think both yours and other peoples testing are valuable for our understanding. More data is never bad as long as you understand how its generated
I applaud your diligence and attention to detail. Insight like this is great. But, I will be keeping a black background because of esthetics. Now, if I were growing for propagation or profit? You'd definitely have me. But, my tank is there to look at.
Love love love this video. I am just finishing up my 5ft and I am going for a white background. I plan to keep it as clean as possible and quite like the way that the white background looks set to scatter the reflection more than clear glass. Sounds like more fill light to me and may do more for the lower sections of my corals than clear glass. As some have said it is a moot point if the reefer doesn't clean the back glass but really I cant see why you wouldn't clean it. The more you clean your back glass the more time your CUC will spend cleaning your scape rather than the glass.
My tank came with a black panel covering the sump area, the main problem is the glossy glass mirrors, fish can get pissed off and swim into the mirroring effect thinking it's a rival. I don't scrape it anymore to clean off spirorbids or algae so it mirrors less and doesn't create an issue but before adding a second clownfish my Mama clown would attack that wall all the time.
What happens if you move the light towards the back? Does it mitigate the drop in par enough to not matter? Also, what if you have a clear back, only you mount some black PVC/Pinseal a couple of millimetres off the back surface? Do you get the same look as we have now, with the advantage of a clear back? Great investigates. Thanks.
and the lighting cords, gotcha. the wall has the special knack for showing you the day after a water change that your water is already yellowing. I still say, if you have the space somewhere (but who does?) put it in the middle of the room! (I don't, that's why I visit local fish stores) btw I have "baby blue" or maybe that english word with a P i think? perrywinkle or something? anyway it seems to accentuate the yellowing, so... maybe I should choose a new wall color. hmmm, priorities.
it makes sense and i appreciate the testing. i can see people using this advice who have frag tanks or other grow out systems. the aesthetics of a black back panel are nice and many would say are worth the par loss from reflection against the back wall of their tank. we take so much time planning, building, cleaning, maintaining so that a tank looks nice beause at the end of the day it is a decoration. nobody wants to see cords and algae on the back glass and painting black helps stop that. Nobody wants a mirrored surface either since its harder to achieve, will show everything, and going to look ugly. if my only goal was to grow coral as efficiently as possible, then yeah maybe a mirror or clear background is better.
None of this is going to matter unless you keep your back wall scrubbed. Also most people can't "just paint the back" if they don't like it. I would guess but I am not positive that if you're highly concerned about par loss from your back wall then you could instead use a sheet of smoked acrylic attached to the back wall rather than painting the back wall directly to get better reflectivity. i.e have a "clear glass background" and then attach to that and some manner a sheet of smoked or high gloss black acrylic. I have done this to the back of my sump when I wanted to have a red looking rear panel on my sump but also wanted to be able to remove the panel to see wiring and plumbing that ran behind the sump when doing troubleshooting. I painted a sheet of acrylic the same color red as my plumbing and then used very heavy duty hook and loop style closure to attach the "background" to my sump
Any photos? You're saying that the acrylic hangs OUTSIDE and behind the sump, right? I'm very interested in sump theory right now because I plan on adding a 29 gallon sump to a 120 gallon temperate tank. (NOT reef, NOT coldwater, local mid-southern california 100%) Any thoughts on lighting timings? I do have the programmed led's. I have the 120 set for local weather, but for the sump do you have any recommendations for timing and dim in/out? Should I just try to sync sunset/sunrise? I haven't needed a sump because I'm only allowed to keep invertebrates without a special license but I'm working on that and want to prepare. Thanks for making me think!
I'm not sure if you're talking about a mirrored or red or tinted background. Reminds me of using aluminum foil on the back as a kid. Makes a huge difference for US... I know a guy who used to hide behind a chair because he was aware that fish can SEE you, so... I agree. my "people" notice the second I wake up in the morning and go into a frenzy. "food guy's here!" I'm very concerned about adding the sump because it's going to change EVERYTHING and if you have any tips please advise.
@@willisgemutlich2608 I mean I can't post photos on TH-cam. But basically I have a sump that's a plain/clear glass sump. I wanted to add a splash of color and hide some cords and hoses that run behind the sump. I took an 1/8" piece of acrylic and cut it to the dimensions of the back wall of my sump. I then spray painted it red using Krylon fusion paint. On the upper and lower corners of the back of my sump I put little squares of super heavy duty "Velcro" (3M Dual lock) the piece of pained acrylic has matching little squares. The squares allow the acrylic panel to be attached and detached to the back (outside) wall of my sump. Due to the thickness of the 3M dual lock squares the painted panel sits/is suspended just slightly off the glass. However when looking straight on or even a bit from the side it just looks like the back wall of the sump is painted red. I think the same concept could be applied at a much larger scale as a background for a display tank. Due to the slight gap (caused by the 3M dual lock) between the sheet of acrylic being used as a background color and the glass I think you may get the benefits of the reflectivity of "plain glass" noted by BRS while still being able to have the background color of your choice. In my case black would be my choice 100% of the time other colors dont give you the same color contrast between the background and the tank, a clear back is just going to be whatever wall color or crap that can be seen though your tank, and a true mirrored background would be very very hard to pull off and in my opinion make the tank look gaudy.
I just painted my tank and it turned out so cool. I painted my old Active Duty unit's logo on the back, and then painted black over it, and on the sides. Love it. Cool test, but I wouldn't change a thing.
Another approach is to use a focused light source that does not put light on the glass at all. This eliminates the need to scrub algae off the glass, because it doesn't grow.
What would happen if you took thin black board and placed it behind the tank 1mm off the surface? Is painting the glass surface the cause of the absorption? If so, I would expect no loss if we simply used a secondary board placed behind the aquarium but not touching the glass. A win/win.
I have an artificial rock wall in the back but all corals I fix on it have great colours and grow, much more than in the middle of the tanks. I have radion g5+t5. Or my light is to strong ( but set just as 55%) or it is because the main light on the side comes from the t5 as the t5 are on the side and the led in the middle ? 🤔
My tank is painted black....had it blue but I prefer the black...corals pop in the contrast more plus the lower par is fine....less scraping back glass imo
allways usefull information as we dont all have the resources to setup al lot of tanks to test things out. i am getting a little tired of the par wars, but it is what it is. If you buy a light to pass a test or you buy a light to cover a tank well and grow corals , ill take the latter. I look at the information and make my own opinion on what works for me in my situation . if youre testing a light for its output in Par there is one test you can do. if youre testing a light in a box of water there is a test you can do. fact is noone runs a light without a tank, and noone runs a light in an empty tank. so a good average of both views fits the best. same light over different tanks wont be alike, some lights will work better in one situation over another.
How about painting the wall of your house behind the tank black or hanging a black sheet or something like that? This might let you keep a black background look but not affect PAR. I'm guessing you will get a mirror like look without it attached directly to the glass though. I was always told black backing is good for the fish, reduces their cage anxiety, the other 3 sides are of course open. Public aquariums do in wall but that is likely due to size, maintenance and public viewing needs but I wonder if it helps the fish only having one surface that is reflective. Just saying PAR is not necessarily the biggest issue when choosing a tank background so let's not go all single factor analysis for choosing a tank background.
GREAT VIDEO AS ALWAYS. WHAT HAPPENS IF YOU HAVE A GLASS TOP,(FULL OR SECTIONS) VS SCREEN VS ACRLIC AND SAND ON BOTTOM OR PURPLE BOTTOM TO REPRESENT BAREBOTTOM TANKS? 🤔🤔🤔
All great questions. We do have a video on light blockage with the clear screen top netting, which ultimately didn't have a big overall impact. The sand bottom or glass top question would be interesting to explore more.
Nice to know, but not a game changer coze at the end the coral will grow at the place he get the most of the light, and we want to grow the coral in the back coral more in the front so the black wall dose this perfectly.
What kind of glass are the tanks made out of? I’m curious if regular rimmed glass tanks contained more par from a light source versus “high clarity” rimless tanks.
These are all Mr. Aqua brand tanks, however, I don't remember if they are the low iron version or not. It's possible that clearer glass could yield more light being put back into the tank, but at the end of the day, the difference is likely negligible.
Both. For an object to be visible it has to reflect light. For an object to have color it has to absorb light. Coraline algae is incredibly porous with microsurface variations, so it has a low specular value, and any light that it bounces to itself has its power reduced via absorption/diffusion a second time. But if it's purple coraline algae, the wavelength coming off it will be purple.
Hello Reef masters Can you please do an investigation about the micro bubbles scrubbing if its work as it should, pros and cons for that. I will be waiting for this video 🌟
There are potentially few gaps in your test methodology... 1. Laser light and normal white light behave diferrently with refraction and reflection. Using a narrow beam of white light might have produced more accurate results. 2. In the ocean there are no vertical surfaces that bounce light back in the manner it does in a tank. You proberbly need to take that into consideration.
Absolutely great points. The goal is to gain more knowledge into the real world application we use this gear for and share that knowledge with fellow hobbyists who are using it to best care for their pets. In that spirit, I think it's a great idea to come back with a quick test using my PolypLab coral flashlight. I'll try it out and share the results later this week!
I got a black background and always wondered why the fish never swam there and behind the rock structure. It now all seems clear to me; it is due to my self created black hole!
Probably there's a more sensible explanation: a powerhead is blowing from behind the rock structure in the back and there's hardly any space (that doesn't expand either) ;)
Coralline would essentially act like a painted background. I would expect almost no light reflection off the back wall if the back of your tank is covered in coralline.
There will definitely be a significant loss in reflection when the light is impeded from the buildup inside the tank. If you're not one to keep the back of the tank clean, then there's no need to worry about the color of the background. ;)
depends on the color of coralline but it should be reflecting a near full spectrum light back, with a tendency to reflect purple/blue so im guessing its reflecting light in the 400+ nm wavelength which our corals benefit from. I have coralline completely covering my barebottom frag tank and sps frags encrust their plugs and continue to grow on the underside of the frags where I believe the coralline is reflecting light towards.
This is what I thought as well. Putting a background behind and not adhered to the glass would still allow light to bounce off both the inside and outside surfaces of the glass, but still provide the sense of depth of view you get from the background.
So what about a tank that has the back wall covered in coraline algae?? Should I assume that the coraline absorbs the beam the same as it being painted? I've always thought the coraline helped bounce the light off of it. So saying that, should I scrape the coraline off the back?? I've pondered this question for a while now.
The difference here is that we are testing the painted outside of the tank, so in every test there was some visible reflection bouncing back into the tank because the glass has two edges. However, with solid (non-translucent/transparent/reflective) material covering the back wall...instead of a faint beam bouncing off the coralline, you'd likely notice a diffuse reflection meaning the coraline is scattering the light in all kinds of directions somewhat similar to a white background.
There is definitely an aesthetic part to this conversation too. We doubt that many reefers will actually stop painting the backs of their tanks, but hopefully it helps them make better choices when placing corals in the back parts of their tank.
This might apply to a coral farm but if painting the back cuts 50% of par I wouldn't care. It's a display tank. A clean back wall is an important part of my display.
I'm curious to see what would the results be for tinting the back black, you can tint glass from 5% to 90%. Would tinting the back allow more light reflection instead of light absorbtion. That could be a good compromise to still get a dark background/black and reduce the decrease in par. I'm really curious about a 20% or 30% tint, very dark, but not as much as a 5% which my hypothesis would say would be to dark and still absorb to much light. Would you guys do a study on the various tint levels?
you guys have access to high tech... what if you just get some dimmable led backs and you can switch em up or down as you please from your phone? that could be interesting...
I have to admit that my favorite tanks are the ones like you have that are a kind like an island with suspended lighting and an open top, fairly shallow but some nooks and crannies under some rockscape in the middle. I don't have enough space to do that, but it's epic to be able to walk around and try to see every angle.
You just mentioned that it’s hard to keep the glass clean and recommended against the white background…..but your test relies on PERFECTLY clean glass. Seems like viewers need to better understand how much a little biofilm affects these PAR numbers. I think it would be pretty easy to make a video about this.
There are absolutely variables of perfectly clean vs. somewhat clean vs. semi-clean vs. somewhat dirty vs. very dirty vs. extremely dirty... sometimes we just need to start somewhere and keep moving forward as we continue to learn. I would call this the first baby step into a very large understanding of the way light interacts with our tanks & animals. The acquisition of new knowledge is a long road. We just keep learning new things and eventually it will change everything. -Randy
@@BRStv thanks for the reply. Good points. I think we could learn more if thought leaders we able to collaborate and work together. Just an idea I wanted to throw out there. I think you will find we would be excited for the opportunity.
@@BRStv I was worried about water damage at first but it turned out not to be problem ..attach each large piece of paper on just the 2 top corners ..enough air gets between the paper and the glass to dry the paper easily , it rairly gets wet anyway .. been doing it that way for 15years now ..it works good and can be moved from tank to tank as you change out setups
of course in a natural reef some "people" like to hide under ledges and around corners, so perhaps some of these "people" might enjoy the "back of the tank"... or the black of the tank. it comes naturally that the bigger the tank, the more options "people" have to move around and find their best little nooks and crannies. it seems like the smaller the tank, the less options with flow, lighting, etc so bigger is better, what are your thoughts? I mean associated hardware to maintain a tank of perhaps 60 gallons or 120 are pretty comparable, right? get a bigger tank! I insist that you are scientists btw. keep hypothesizing, testing and reporting. we're all learning, thanks to you. I've had more trouble with my 3.7 gallon than my 120 to be honest. It's just a razor's edge if anything starts going awry.
Can I add. You can still achieve the same par readings with any colour painted back. Simply have a small 1 or 3 mm gap between the glass and the solid colour you want by using a board or better yet paint the wall that the tank is going to go up against white black or blue or stick film to the wall lol
Do you think that the puck light, because it is coming from a small singular point, would loose more light in the painted back tank than a panel light that emits light more evenly from a large area?
My hypothesis would be that they would both be pretty similar. Reef lighting, whether it be a small pendant style light or panel style light, all emit light 360 degrees. If you look at the par charts from the ATI T5 videos that we've done in the past, you still see that distinct par drop in the back of the tank when the back is black.
I think that all this proves is that you should own a PPFD meter as the choices you make in scape, type of tank, painted or not, how often the glass is cleaned, lighting and their settings/mounting, water filtration method (turbidity), flow (microbubbles) and so on make it almost impossible to determine exactly what PPFD a tank will have. However I think both yours and other peoples testing are valuable for our understanding. More data is never bad as long as you understand how its generated
My back glass is currently being “painted” in green star polyps… but this is a super cool experiment!!
I applaud your diligence and attention to detail. Insight like this is great.
But, I will be keeping a black background because of esthetics.
Now, if I were growing for propagation or profit? You'd definitely have me.
But, my tank is there to look at.
Guess it's back to the old hanging vinyl photos of freshwater plants in a saltwater tank 😜
😂😂🤣
Love love love this video. I am just finishing up my 5ft and I am going for a white background. I plan to keep it as clean as possible and quite like the way that the white background looks set to scatter the reflection more than clear glass. Sounds like more fill light to me and may do more for the lower sections of my corals than clear glass. As some have said it is a moot point if the reefer doesn't clean the back glass but really I cant see why you wouldn't clean it. The more you clean your back glass the more time your CUC will spend cleaning your scape rather than the glass.
My tank came with a black panel covering the sump area, the main problem is the glossy glass mirrors, fish can get pissed off and swim into the mirroring effect thinking it's a rival. I don't scrape it anymore to clean off spirorbids or algae so it mirrors less and doesn't create an issue but before adding a second clownfish my Mama clown would attack that wall all the time.
What happens if you move the light towards the back? Does it mitigate the drop in par enough to not matter? Also, what if you have a clear back, only you mount some black PVC/Pinseal a couple of millimetres off the back surface? Do you get the same look as we have now, with the advantage of a clear back?
Great investigates. Thanks.
Win for peninsula tanks :)
Is there any changes from using a pre colored backdrop, or cloth behind the tank.
I think that's going to be the way to get the best of both worlds. I'll work up a quick test this week and share.
Please BRS I am wondering about acrylic tanks compared to glass tanks do a investigates to compared and contrast the 2
You don't ever want an acrylic reef tank...
@@ronniekregar3482 why not wouldn't the seams be stronger and last longer than the glass seams that are glued
That's all well and good, but a black background looks way better than seeing through to my wall.
and the lighting cords, gotcha. the wall has the special knack for showing you the day after a water change that your water is already yellowing. I still say, if you have the space somewhere (but who does?) put it in the middle of the room! (I don't, that's why I visit local fish stores) btw I have "baby blue" or maybe that english word with a P i think? perrywinkle or something? anyway it seems to accentuate the yellowing, so... maybe I should choose a new wall color. hmmm, priorities.
Gsp is always an option
@@Slayyyter_bitxh I'd rather have aiptasia. Less invasive. lol
it makes sense and i appreciate the testing. i can see people using this advice who have frag tanks or other grow out systems. the aesthetics of a black back panel are nice and many would say are worth the par loss from reflection against the back wall of their tank. we take so much time planning, building, cleaning, maintaining so that a tank looks nice beause at the end of the day it is a decoration. nobody wants to see cords and algae on the back glass and painting black helps stop that. Nobody wants a mirrored surface either since its harder to achieve, will show everything, and going to look ugly. if my only goal was to grow coral as efficiently as possible, then yeah maybe a mirror or clear background is better.
What about a purple background? Back wall of my aquarium is covered in coraline algae 🤣
None of this is going to matter unless you keep your back wall scrubbed. Also most people can't "just paint the back" if they don't like it. I would guess but I am not positive that if you're highly concerned about par loss from your back wall then you could instead use a sheet of smoked acrylic attached to the back wall rather than painting the back wall directly to get better reflectivity. i.e
have a "clear glass background" and then attach to that and some manner a sheet of smoked or high gloss black acrylic. I have done this to the back of my sump when I wanted to have a red looking rear panel on my sump but also wanted to be able to remove the panel to see wiring and plumbing that ran behind the sump when doing troubleshooting. I painted a sheet of acrylic the same color red as my plumbing and then used very heavy duty hook and loop style closure to attach the "background" to my sump
Any photos? You're saying that the acrylic hangs OUTSIDE and behind the sump, right? I'm very interested in sump theory right now because I plan on adding a 29 gallon sump to a 120 gallon temperate tank. (NOT reef, NOT coldwater, local mid-southern california 100%) Any thoughts on lighting timings? I do have the programmed led's. I have the 120 set for local weather, but for the sump do you have any recommendations for timing and dim in/out? Should I just try to sync sunset/sunrise? I haven't needed a sump because I'm only allowed to keep invertebrates without a special license but I'm working on that and want to prepare. Thanks for making me think!
I'm not sure if you're talking about a mirrored or red or tinted background. Reminds me of using aluminum foil on the back as a kid. Makes a huge difference for US... I know a guy who used to hide behind a chair because he was aware that fish can SEE you, so... I agree. my "people" notice the second I wake up in the morning and go into a frenzy. "food guy's here!" I'm very concerned about adding the sump because it's going to change EVERYTHING and if you have any tips please advise.
@@willisgemutlich2608 I mean I can't post photos on TH-cam. But basically I have a sump that's a plain/clear glass sump. I wanted to add a splash of color and hide some cords and hoses that run behind the sump. I took an 1/8" piece of acrylic and cut it to the dimensions of the back wall of my sump. I then spray painted it red using Krylon fusion paint. On the upper and lower corners of the back of my sump I put little squares of super heavy duty "Velcro" (3M Dual lock) the piece of pained acrylic has matching little squares. The squares allow the acrylic panel to be attached and detached to the back (outside) wall of my sump. Due to the thickness of the 3M dual lock squares the painted panel sits/is suspended just slightly off the glass. However when looking straight on or even a bit from the side it just looks like the back wall of the sump is painted red. I think the same concept could be applied at a much larger scale as a background for a display tank. Due to the slight gap (caused by the 3M dual lock) between the sheet of acrylic being used as a background color and the glass I think you may get the benefits of the reflectivity of "plain glass" noted by BRS while still being able to have the background color of your choice. In my case black would be my choice 100% of the time other colors dont give you the same color contrast between the background and the tank, a clear back is just going to be whatever wall color or crap that can be seen though your tank, and a true mirrored background would be very very hard to pull off and in my opinion make the tank look gaudy.
@@chaostactics aha gotcha. thanks for responding.
I just painted my tank and it turned out so cool. I painted my old Active Duty unit's logo on the back, and then painted black over it, and on the sides. Love it. Cool test, but I wouldn't change a thing.
Another approach is to use a focused light source that does not put light on the glass at all. This eliminates the need to scrub algae off the glass, because it doesn't grow.
What would happen if you took thin black board and placed it behind the tank 1mm off the surface? Is painting the glass surface the cause of the absorption? If so, I would expect no loss if we simply used a secondary board placed behind the aquarium but not touching the glass. A win/win.
I think that's going to be the way to get the best of both worlds. I'll work up a quick test this week and share.
@@BRStvanswer?
The title caught my eye... I've never been a fan of the painted tank backgrounds
I plan on getting a low lead glass tank… not happy with the greenish tint. I wonder what the reflectivity difference is if any
Awesome test....
I like using mirror window tint. I'm actually shocked it wasn't the best
So did you paint the inside or the outside of the backpanel?
I use static cling window tint instead if paint. Light still passes through it. I wonder how that compares to the pained black option.
This is why I have a peninsula tank 🙂
Thank you for the video and the information. It seems that peninsula tanks are best for growing coral
Very cool, I live the science and the useful conclusions !
Jim
I have an artificial rock wall in the back but all corals I fix on it have great colours and grow, much more than in the middle of the tanks. I have radion g5+t5. Or my light is to strong ( but set just as 55%) or it is because the main light on the side comes from the t5 as the t5 are on the side and the led in the middle ? 🤔
My tank is painted black....had it blue but I prefer the black...corals pop in the contrast more plus the lower par is fine....less scraping back glass imo
Hmm. That’s it? I’m fine with that, will keep painting the back black.
would also like to see how much a glass lid takes par down compared to open top. im sure a dirty glass lid blocks alot of par
allways usefull information as we dont all have the resources to setup al lot of tanks to test things out.
i am getting a little tired of the par wars, but it is what it is. If you buy a light to pass a test or you buy a light to cover a tank well and grow corals , ill take the latter. I look at the information and make my own opinion on what works for me in my situation . if youre testing a light for its output in Par there is one test you can do. if youre testing a light in a box of water there is a test you can do.
fact is noone runs a light without a tank, and noone runs a light in an empty tank. so a good average of both views fits the best.
same light over different tanks wont be alike, some lights will work better in one situation over another.
How about painting the wall of your house behind the tank black or hanging a black sheet or something like that? This might let you keep a black background look but not affect PAR. I'm guessing you will get a mirror like look without it attached directly to the glass though. I was always told black backing is good for the fish, reduces their cage anxiety, the other 3 sides are of course open. Public aquariums do in wall but that is likely due to size, maintenance and public viewing needs but I wonder if it helps the fish only having one surface that is reflective. Just saying PAR is not necessarily the biggest issue when choosing a tank background so let's not go all single factor analysis for choosing a tank background.
What about if someone uses like a background like paper behind it or like construction paper in the back
I think that's going to be the way to get the best of both worlds. I'll work up a quick test this week and share.
Yoooo Mr.Chilli!!!! I love you
Iv left the back natural, 6ft x 27inch pane of glass can hold a lot of bacteria and algae for the fish.
I wonder if it would have the same effect if the tank had window tint instead of paint
Ok, I haven't got my upgraded tank yet so this is interesting. I'm curious about painting the background blue.
Don’t paint your background any color - it’s literally physics
GREAT VIDEO AS ALWAYS. WHAT HAPPENS IF YOU HAVE A GLASS TOP,(FULL OR SECTIONS) VS SCREEN VS ACRLIC AND SAND ON BOTTOM OR PURPLE BOTTOM TO REPRESENT BAREBOTTOM TANKS? 🤔🤔🤔
All great questions. We do have a video on light blockage with the clear screen top netting, which ultimately didn't have a big overall impact. The sand bottom or glass top question would be interesting to explore more.
Nice to know, but not a game changer coze at the end the coral will grow at the place he get the most of the light, and we want to grow the coral in the back coral more in the front so the black wall dose this perfectly.
What kind of glass are the tanks made out of? I’m curious if regular rimmed glass tanks contained more par from a light source versus “high clarity” rimless tanks.
Shouldn't have anything to do with it as the light isn't entering through the glass.
These are all Mr. Aqua brand tanks, however, I don't remember if they are the low iron version or not. It's possible that clearer glass could yield more light being put back into the tank, but at the end of the day, the difference is likely negligible.
Does coraline algae reflect or absorb light?
Both. For an object to be visible it has to reflect light. For an object to have color it has to absorb light. Coraline algae is incredibly porous with microsurface variations, so it has a low specular value, and any light that it bounces to itself has its power reduced via absorption/diffusion a second time. But if it's purple coraline algae, the wavelength coming off it will be purple.
I see a red tank and I want it painted black......
I had too....I'll see myself out.
😂🤣
Hello Reef masters
Can you please do an investigation about the micro bubbles scrubbing if its work as it should, pros and cons for that.
I will be waiting for this video 🌟
I’ve never understood why folks paint the tank. I just cover a piece of hardboard and slide it down between the tank and the wall.
Hmm, I could redo my Pond Shield on my DIY build. If using window tint with different tint percentages, will the results vary dramatically?
Window tint would be a good part two to this experiment 🤔
There are potentially few gaps in your test methodology...
1. Laser light and normal white light behave diferrently with refraction and reflection. Using a narrow beam of white light might have produced more accurate results.
2. In the ocean there are no vertical surfaces that bounce light back in the manner it does in a tank. You proberbly need to take that into consideration.
Absolutely great points. The goal is to gain more knowledge into the real world application we use this gear for and share that knowledge with fellow hobbyists who are using it to best care for their pets. In that spirit, I think it's a great idea to come back with a quick test using my PolypLab coral flashlight. I'll try it out and share the results later this week!
Well...who'd a thunk it? That's crazy...about to go home and take my background off!
I just finished painting the back of my tank black 1 hour before this dropped.
Nothing wrong with a painted background! Just use the info here to properly place your corals and set your lights :)
Me too and also the sides hahahaha
Interesting! Now what happens if you have a background full of coraline?? Lol
Coralline would almost certainly give the same result as if the background were painted.
I got a black background and always wondered why the fish never swam there and behind the rock structure. It now all seems clear to me; it is due to my self created black hole!
Probably there's a more sensible explanation: a powerhead is blowing from behind the rock structure in the back and there's hardly any space (that doesn't expand either) ;)
What about coralline algae on the back?
Coralline would essentially act like a painted background. I would expect almost no light reflection off the back wall if the back of your tank is covered in coralline.
This is why I let coralline completely overgrow the back of my tank.
What about a background covered in Coraline like most well established tanks are going to have. How does this change the reflected light.
There will definitely be a significant loss in reflection when the light is impeded from the buildup inside the tank. If you're not one to keep the back of the tank clean, then there's no need to worry about the color of the background. ;)
depends on the color of coralline but it should be reflecting a near full spectrum light back, with a tendency to reflect purple/blue so im guessing its reflecting light in the 400+ nm wavelength which our corals benefit from. I have coralline completely covering my barebottom frag tank and sps frags encrust their plugs and continue to grow on the underside of the frags where I believe the coralline is reflecting light towards.
But what happens if the background isn't touching the glass?
This is what I thought as well. Putting a background behind and not adhered to the glass would still allow light to bounce off both the inside and outside surfaces of the glass, but still provide the sense of depth of view you get from the background.
Man I love science!
So what about a tank that has the back wall covered in coraline algae?? Should I assume that the coraline absorbs the beam the same as it being painted? I've always thought the coraline helped bounce the light off of it. So saying that, should I scrape the coraline off the back?? I've pondered this question for a while now.
The difference here is that we are testing the painted outside of the tank, so in every test there was some visible reflection bouncing back into the tank because the glass has two edges. However, with solid (non-translucent/transparent/reflective) material covering the back wall...instead of a faint beam bouncing off the coralline, you'd likely notice a diffuse reflection meaning the coraline is scattering the light in all kinds of directions somewhat similar to a white background.
This video is going to make a lot of people start pealing of the paint on the tanks 🤦♂️
There is definitely an aesthetic part to this conversation too. We doubt that many reefers will actually stop painting the backs of their tanks, but hopefully it helps them make better choices when placing corals in the back parts of their tank.
Almost did mines 😂
This might apply to a coral farm but if painting the back cuts 50% of par I wouldn't care. It's a display tank. A clean back wall is an important part of my display.
We felt the same after the first time we cleaned the BRS160!
I wonder how a coralline algae glass covered tank holds up to light reflection.
I would expect coralline to essentially act as a background and limit the amount of light reflection to almost none.
I already need 10 spotlight design lights since its a cash grab.. so il just add another ..
Mines covered in coraline algae
and if you keep the black but space it a cm off the glass?
In theory, that should make the light act like there is no background at all 🙂
Only thing painting the back of my tank is coralline 😂
In conclusion: painting or not painting backwalls is irrelevant.
I'm curious to see what would the results be for tinting the back black, you can tint glass from 5% to 90%. Would tinting the back allow more light reflection instead of light absorbtion. That could be a good compromise to still get a dark background/black and reduce the decrease in par. I'm really curious about a 20% or 30% tint, very dark, but not as much as a 5% which my hypothesis would say would be to dark and still absorb to much light. Would you guys do a study on the various tint levels?
YES!
I Just said that! 😆
you guys have access to high tech... what if you just get some dimmable led backs and you can switch em up or down as you please from your phone? that could be interesting...
I have to admit that my favorite tanks are the ones like you have that are a kind like an island with suspended lighting and an open top, fairly shallow but some nooks and crannies under some rockscape in the middle. I don't have enough space to do that, but it's epic to be able to walk around and try to see every angle.
What if the back panel was made from a mirror, instead of placing one behind it or giving the tank a paint coat?
I would expect very similar results
point a laser at me when I have a painted back wall and again if I have an unpainted back wall. I'm 25% less happy with no paint
Very informative. Science 🤯..
Did you stick your head in for the test as well? Ya know, for science 😉
What about a realistic coralline purple 🤣
You just mentioned that it’s hard to keep the glass clean and recommended against the white background…..but your test relies on PERFECTLY clean glass. Seems like viewers need to better understand how much a little biofilm affects these PAR numbers. I think it would be pretty easy to make a video about this.
There are absolutely variables of perfectly clean vs. somewhat clean vs. semi-clean vs. somewhat dirty vs. very dirty vs. extremely dirty... sometimes we just need to start somewhere and keep moving forward as we continue to learn. I would call this the first baby step into a very large understanding of the way light interacts with our tanks & animals. The acquisition of new knowledge is a long road. We just keep learning new things and eventually it will change everything. -Randy
@@BRStv thanks for the reply. Good points. I think we could learn more if thought leaders we able to collaborate and work together. Just an idea I wanted to throw out there. I think you will find we would be excited for the opportunity.
To me this means just add supplement lights such as an orphek bar and you'll mitigate that 10% loss easily
Not a bad idea to gain PAR in a targeted area!
I got to say it...1st!!! Never been this early for a video before...😅
It's far better to use black construction paper attached with electrical tape ..no need to paint
The downside I could see there would be durability if there were any drips or spills.
@@BRStv I was worried about water damage at first but it turned out not to be problem ..attach each large piece of paper on just the 2 top corners ..enough air gets between the paper and the glass to dry the paper easily , it rairly gets wet anyway .. been doing it that way for 15years now ..it works good and can be moved from tank to tank as you change out setups
of course in a natural reef some "people" like to hide under ledges and around corners, so perhaps some of these "people" might enjoy the "back of the tank"... or the black of the tank. it comes naturally that the bigger the tank, the more options "people" have to move around and find their best little nooks and crannies. it seems like the smaller the tank, the less options with flow, lighting, etc so bigger is better, what are your thoughts? I mean associated hardware to maintain a tank of perhaps 60 gallons or 120 are pretty comparable, right? get a bigger tank! I insist that you are scientists btw. keep hypothesizing, testing and reporting. we're all learning, thanks to you. I've had more trouble with my 3.7 gallon than my 120 to be honest. It's just a razor's edge if anything starts going awry.
ya ! but who the f!!!k clean the back of their tank when they are next to a wall. The back of the tank will get dirty or full of coralline so....
Can I add. You can still achieve the same par readings with any colour painted back. Simply have a small 1 or 3 mm gap between the glass and the solid colour you want by using a board or better yet paint the wall that the tank is going to go up against white black or blue or stick film to the wall lol
This is why I didnt go with painting my tank
Do you think that the puck light, because it is coming from a small singular point, would loose more light in the painted back tank than a panel light that emits light more evenly from a large area?
My hypothesis would be that they would both be pretty similar. Reef lighting, whether it be a small pendant style light or panel style light, all emit light 360 degrees. If you look at the par charts from the ATI T5 videos that we've done in the past, you still see that distinct par drop in the back of the tank when the back is black.
Lol, watch how many ridiculously unnatural looking tanks with white backgrounds are gonna start popping up now...
I've just googled some images. They don't look that bad. Some are actually aesthetically pleasing
aestetics over efficiency all the way though, anything but a clear or black background looks extremely crappy. (especially blue, bleu is so ugly)
This is common sense. Yes the back is less in the back. Who cares? Have our tanks been suffering? No
nah i'll keep it black hehe
Meh. It’s just PAR for the course.
🤣
Bla bla but everything looks better with black back
True! But now you know that the corals in the back of the tank might not be seeing as much par as you think 😃
@@BRStv yes and i thank you for the info 👍 you guys are the best !
1st