mirrors ???

donald altman

New member
Hey gang I am fixing to revamp a 22.5 gallon breeder that I stopped using awhile back.

It is 36x12x12
I am going to make it into a frag grow out.. I have all the equipment I need so I am just toying with a few last minute ideas.. has anyone ever used a metalic paint on the outside of the frag tanks to reflect more light around in the tank itself.. like
instead of painting the back black why not paint it with a mirror creating color or plain old white to reflect as much light as possible. I don't plan on using this tank to view at all and was even thinking about doing the complete outside of the tank this way. The tank is soooo shallow I could look down very easyly into to spot a frag it will be barebottom with eggcrate with string corners I can just raise to the surface or completely out of the water to grab my frag.

I think this way I could get away with less intense light and make sure every frag gets light from all angles.
 

Psychographic

New member
<a href=showthread.php?s=&postid=8085416#post8085416 target=_blank>Originally posted</a> by hamburglar
Your sidewalls are already mirrors if your lights are on top. Just take a look down from the top.

Sorry but you are wrong. Stick your head IN the water and see if it still reflects like a mirror.
 

T Man

~PPPPPPP~
It won't take algae too long to cover the inside of the tank. Losing all of the paints ability to "reflect" light. I don't "scrape" algae from my prop tank because it's not an issue with looks as much as it is with the main.
I think your idea about the mirror back is a good one, if you keep up with the scraping I'm sure it would do as you want. A good start on your mirror paint would probably ask around the glass companies or maybe a "Tint" shop. Good Luck Tinman
 

Ken668

New member
I have done the mirror trick on my current prop tank. I bought a case of 1'x1' mirror tiles from Lowes and put small dabs of silicone in the corners to hold them to the ouside of the tank. I did this on only 3 sides of the tank as I still wanted to be able to view from the front. Tinman is correct, you need to keep the glass relatively clean for optimum light reflection. Although if you can see anything reflecting from the mirror (even through algae), it's still working to some degree.
 

hamburglar

New member
Psychographic, do you stick your lights into the water????

This is kind of how fiber optics transmit (read contain for distance) light. The only light that comes out of the side walls is lindirect ight reflecting off of another surface inside the water. So, yes, if you place your lights IN the water they will shine directly throught the sidewalls.
 

raaden

In Memoriam
Notwithstanding the incidence and refraction (I am not touching that one ;) too messy ) do not use the paint. It is impossible to get a good coating. My wife tried to use it on a dresser and also on a couple of other things, with terrible results. Go with a tinting film, much easier and can be removed if needed. You can find it with Automotive window tintings at a parts shop, if your state allows it, or on the internet. The film is also much cheaper than the paint.

Now back to your previously scheduled discussion...
 

hamburglar

New member
Ok Raaden, next time your in a drunkin brawl your on your own :)

Actually the tint does sound like a good idea because you can easily scrape it off if you decide to do something different with the tank.
 

cmolio2

New member
I agree with the tinting idea. You can buy fully mirrored tinting film at Kragen or online. You could also get it in many colors. Amber, Yellow, Silver, Red, Blue,etc. Blue or yellow seems like they would give a great amount of Actinic reflection.
 

raaden

In Memoriam
Ok since I have been drug into the discussion...

The real answer is that it is a bit of both. The glass sides of the tank act as both mirrors and pass-thrus. Let me describe what I mean first then I will get into the reason for it. If the sides were completely mirrored there would be no light getting out of the tank and the tank would look really dark when viewing straight through the glass. But also Ham is right that when you view it from the top or from a side looking angle through one pane of glass looking at another it will be a mirror. Try it and you will see what I mean. I used to do this so that I could see some fish that hid in a cave on the backside of my setup.

The reason for this is that water has an odd angle of refraction. Hams article describes it very well. When you are looking straight into it you are seeing reflected light from things that are at a 13° angle not something that is directly in front of you. This is why when you put your leg in a pool the legs seems "broken" everybody has seen that. If you take these angles and a little bit of geometry you can easily see how those 13°'s add up to reflect light around.

Now the issue of is a mirror finish going to increase the light in the tank. Of course the more light entering the water, no matter where it is from, the better it is. Especially if you are using fluorescent only lighting, it makes less of an effect when using MH as there is less light scatter with point source light. Does it make enough of a gain to warrant using it on a medium sized (>50G) tank. Not really, unless you are going to put it on the inside of the glass. Why is this... consider fluorescents only

1. The light coming from the top will be scattered equally and the way that reflectors are made it will be directed straight down so about 60% of the light will never make it to the edges.
2. Of the light that does make it to the edges about 10% of it will be reflected just by the incidence angle of the water interface, and a mirror finish will not make a difference.
3. The light that does make it to the edges and is not naturally reflected has already traveled through a couple of feet of water and must travel through another couple of feet of water once reflected to get to anything that could absorb it. This much water reduces the light output by about 30%... just from the water
4. No matter how much you clean your inside tank walls you will still have a light coating of algea on it. Clean your glass tonight and then tomorrow night look down the side of the glass and see how fuzzy it is. This algea reduces a significant amount of light that can be reflected on the water interface. Not sure how much but after looking at it I would guess about 20-30% again.
5. Glass is an insulator and tempered glass is a huge insulator. If your tank is using 1/4th inch tempered glass (most common). that thickness of tempered glass reduces light intensity by about 6-8% depending on a few things. Now consider that you have to do through the glass twice to get back into the tank and you have lost another 12%
6. The best reflective films reflect about 96% of light. That means you are losing another 4%.

After you lose all of that light you might be getting a boost of about 6-10% of the light that is coming from your source. Is it worth it... That is up to you, but it would seem to me that there are better ways of getting light into the tank than mirror coatings on the sides of the tank. A better set of ballasts will easily give that much gain and does not require anywhere near as much work... especially if you ever want to get the tint or paint off again.
 
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Psychographic

New member
<a href=showthread.php?s=&postid=8096607#post8096607 target=_blank>Originally posted</a> by hamburglar
Psychographic, do you stick your lights into the water????

This is kind of how fiber optics transmit (read contain for distance) light. The only light that comes out of the side walls is lindirect ight reflecting off of another surface inside the water. So, yes, if you place your lights IN the water they will shine directly throught the sidewalls.

I'm not sure where you are going with this. If the sides of your tank reflected like mirrors, how would anything see out of the tank? I know for sure the inhabitants of every tank I've ever owned were able to see through the glass. You see a reflection from outside the tank, but not from inside the tank. I might be saying the exact thing you've said, I'm not sure what you meant.
 

jessp

New member
sounds like your gonna just have to try, and let us know, thats what the bottom line is going to be
 

hamburglar

New member
Psychographic,

I think it is more of a point of view thing. When we look down from the top of the tank, we have a refraction effect from both the water surface, and then an even greater refraction effect on the sidewalls. This makes them act as mirrors (almost 100%), but only from that point of view. The lights are sitting on top of the tank and out of the water so their light output is also refracted at an angle on the water surface, and then at a greater angle by the sidewalls.

From inside the water, light is only refracted one time by the glass, so this is very minor and the sidewalls would not act very much like mirrors.

So yes, you are also correct in a way. I was just trying to say that from the aquarium lights point of view, the sidewalls are almost 100% reflective already.

Here is the down and dirty.....if the mirrors are free, go for it. If you have to pay for them, then energy saved will probably never equal the upfront cost.
 

Psychographic

New member
The corals are in the tank, so the walls of the tank will do no good to help reflect light for there growth. I think that was the point of this thread. Am I correct?
 

hamburglar

New member
I think he was just trying to keep as much light inside the tank as possible to increase bulb efficiency....just let it bounce around and strike the corals from as many angles as possible.
 
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