# Plexiglass top



## Dan (Aug 6, 2005)

My old glass top had a plastic strip down the middle that blocked a lot of light, so I got a piece of plexiglass cut to fit the top. It appears to let 100% of the light through, but I have heard that plexiglass can block some certain wavelengths of light. Does anyone know if this would include wavelengths that plants need, or is this just an old wife's tale? I have a 6700 pc if that helps or matters.

Dan


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## Gumby (Aug 1, 2005)

I think it blocks mainly UV wavelengths... <400nm, again, I think.


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## czado (May 26, 2005)

Everytime I've tried plexi it sagged on me, even 1/4". I've been told it has an affinity for water. Lexan worked great, and I would assume acrylic is better.


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## JanS (Apr 14, 2004)

When I tried Plexiglass, it was a total failure. I don't recommend it at all, since I just wasted the money on it, and wound up replacing it with real glass in a short time, anyway.

Warping is the main issue with it.


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## Clone (Mar 9, 2005)

JanS:


> When I tried Plexiglass, it was a total failure. I don't recommend it at all, since I just wasted the money on it, and wound up replacing it with real glass in a short time, anyway.
> 
> Warping is the main issue with it.


I couldn't agree more. The tank top should not be a maintenance concern.


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## tazcrash69 (Oct 24, 2005)

Another thing about Plexiglas is that it scratches fairly easily, which becomes a nightmare when you try to clean algae. Also the more scratches, the more light is being blocked, and not making into the tank.

Thick Acrylic works better, but still has issues with scratching compared to glass.


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## cferrell (Oct 5, 2005)

Plexi is hydrophillic - meaning it absorbs water. That's why it bends, the side nearer the water absorbs water and expands. If you turn it over, it will slowly bend the other way. If you let it dry out, it will go back to normal. A way around it is to get a piece thick enough so that it won't bend.

I typically just don't use tops though, unless it's a Q-tank and the fish are more prone to jump than in a fully planted tank where they seem more comfortable and don't jump as often (at least for me).


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## Dan (Aug 6, 2005)

Thanks for the help. I wish I had asked this question before I wasted lots of money. The top started to bow after 2 days. I am definately trashing it and getting a piece of glass. Is there any type or thickness to get that anyone recommends?


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