Plexiglass Tank Cover

[cmb1177]

I have an old hex front flat back tank and I'd like to make a plexiglass cover so I can put a new light fixture on top. Question is, would there be any sort of problem in using plexiglass? I obviously plan to lay a compact flourescent light fixture right on it, and I'm wondering if it'd be safe. I don't know if any heat would compromise the integrity, or if heat would cause to plexi to release any sort of gases. I

If this seems like a ridiculous question, I apologize. I know nothing about this kind of thing. Thanks!

 

[JimShorts]

You'll be fine with a plexi cover. A lot of tanks use plastic covers, and I have seen some that actually were plexiglass. In fact, I'm going to modify mine, since my light is too big to fit on it, so I'm either going to use glass or plexiglass, I haven't decided yet. A compact fluorescent bulb isn't going to put out enough heat to cause any harm as far as I know.

 

[Schmill]

Please excuse my ignorance, but is plexi-glass basically acrylic sheet?

 

[cmb1177]

JimShorts,

I was thinking of using glass, too, but I've been leaning towards the durability of plexiglass.

Scmill,

According to Wikipedia:

"Poly(methyl methacrylate) (PMMA) poly(methyl 2-methylpropenoate) is a thermoplastic and transparent plastic....It is sold by the tradenames Plexiglas, Vitroflex, Limacryl, R-Cast, Per-Clax, Perspex, Plazcryl, Acrylex, Acrylite, Acrylplast, Altuglas, Polycast, Oroglass and Lucite and is commonly called acrylic glass or simply acrylic."

I didn't realise they were all the same....thanks for bringing it up!

 

[Schmill]

Hmmm... carrying on from that post on the Wiki:

The material is often used as an alternative to glass. Differences in the properties of the two materials include:

• PMMA is lighter: its density (1190 kg/m3) is about half that of glass.
• PMMA does not shatter
• PMMA is softer and more easily scratched than glass. This can be overcome with scratch-resistant coatings.
• PMMA can be easily formed, by heating it to 100 degrees Celsius.
  
  [*]PMMA transmits more light (92% of visible light) than glass.
  [*]Unlike glass, PMMA does not filter UV (ultraviolet) light. PMMA transmits UV light, at best intensity, down to 300 nm. Some manufacturers coat their PMMA with UV films to add this property. On the other hand, PMMA molecules have great UV stability compared to polycarbonate.

The 2 points in red interest me. If you have a planted aquarium won't the plants NEED UV light (although I have no idea at what wavelength).
If you ignore the fact that the arcylic is more easily scratched than glass, then all of the other points would seem to point in the direction of acrylic being a BETTER tank cover / condesation cover than glass?

 

[Schmill]

With regards to plants NEEDING UV etc, I've answered my own question after finding a most excellent web page

• 200 - 280 nm
  UVC ultraviolet range which is extremely harmful to plants because it is highly toxic.
• 280 - 315 nm
  Includes harmful UVB ultraviolet light which causes plants colors to fade.
• 315 - 380 nm
  Range of UVA ultraviolet light which is neither harmful nor beneficial to plant growth.
• 380 - 400 nm
  Start of visible light spectrum. Process of chlorophyll absorption begins. UV protected plastics ideally block out any light below this range.
• 400 - 520 nm
  This range includes violet, blue, and green bands. Peak absorption by chlorophyll occurs, and a strong influence on photosynthesis. (promotes vegetative growth)
• 520 - 610 nm
  This range includes the green, yellow, and orange bands and has less absorption by pigments.
• 610 - 720 nm
  This is the red band. Large amount of absorption by chlorophyll occurs, and most significant influence on photosynthesis. (promotes flowering and budding)
• 720 - 1000 nm
  There is little absorption by chlorophyll here. Flowering and germination is influenced. At the high end of the band is infrared, which is heat.
• 1000+ nm
  Totally infrared range. All energy absorbed at this point is converted to heat.

 

[cmb1177]

So it seems acrylic is better in terms of transmission, but it must be UV coated. You might've saved me, there....

Thanks, Schmill; nice job!

 

[Schmill]

Well, it does seem as if acrylic will pass more of the visible light yes, so is better in that respect, but I don't think it REALLY matters about the UV coating, (unless of course you have strong sunlight streaming in through the top of the tank!).

The website I got the information from was a greenhouse website! Lighting Guide

I've also got most of the information wrapped up in another thread on here:

Lighting Equivalents, Incandescent, T12, T5 and more!



I think I might try acrylic to be honest, as at the moment I can't seem a reason not to, and it seems like it will be easier to cut that glass, (and safer if it breaks!)

 

[Stephanie p]

I was thinking of doing the same to my tank.....where would you get the acrylic from?

 

[Geigetron343]

Hi all, I'm very interested in getting some sort of non-glass cover, because I want to cut holes for a fish bridge (if you're not familiar, it's shown below).

It's basically a tube going over the tank that allows water to pass through (AND FISH!!! ). This would be beneficial for a few reasons, namely easier WCs, looking cool, and keeping parameters stable (from what I understand, more water=more stability). I have several fish, including a rope fish, who will jump out if I don't have a lid on the tank, and it seems like the plastics are easier to cut and not break. Have any of you installed an acrylic lid yet? How are they for cutting holes in (about 5" diameter)? I'm also interested in PCB, because of its increased visibility/clarity and higher impact and stress resistance. Has anyone used PCB?

Thanks a bunch!
-Tron

[EDIT] BTW Stephanie, you could get acrylic at Menards, Home Depot, or Fleet Farm (or similar stores). You will need to cut it to fit, unless you can bat you eyelashes and get someone at the store to do it for you (totally not implying you can't cut your own--I could, but I'd rather have someone do it for me quickly).

 

[Colin_T]

You are probably better off starting a new thread for this topic. The current thread here is from 2008.

 

[Geigetron343]

Lol I see... how do I do that? (I'm a noob)

 

[Colin_T]

If you left click "Forums" at the top of the page it will take you to the following link.
http://www.fishforums.net/

Scroll down the page until you find a heading that suits the subject. For this subject you would use "Tropical Discussion", see following link.
http://www.fishforums.net/forums/tropical-discussion.1/

Scroll down to the bottom of that page and click "Post New Thread". Then go from there.

 

[Geigetron343]

Thanks a bunch!