# Solid sheet polycarbonate vs Twin wall polycarb vs tempered glass covers?



## torque6 (Jun 7, 2008)

Hello, I have a 3FT tank and am looking for a tank cover to prevent fish from jumping out and also to help lessen humidity in my room.

I bought a 45x45 cm, 2mm thick, solid sheet polycarbonate today and it kinda flexes alot. So wasted money on that.

Twin wall polycarb seems thicker and will be more rigid, but heard that it will decrease PAR somewhat. I am already running a low light setup, would this be recommended?

Tempered glass is another option but I am worried about the weight. Another concern is the inlet and outflow pipes stick out into the tank for about 1-2 cm, not sure if glass can be cut with irregular shapes (a square glass with a clearance at the right hand corner of 2x2cm). What would be the recommended thickness for 2 pieces of 45x45cm to cover a 3FT tank?

Any suggestions would be appreciated.


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## ichy (Apr 6, 2015)

egg crate under acrylic? All the plastics tend to sag over time.


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## torque6 (Jun 7, 2008)

ichy said:


> egg crate under acrylic? All the plastics tend to sag over time.


That is a good suggestion, but I am using a lily pipe, thus my water level is just 2 cm to the top of the tank.


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## natemcnutty (May 26, 2016)

Polycarbonate is my favorite because I can customize it, and it won't get broken when someone does something stupid... 

The thickness is very important and your main issue here, but I think you also shorted on material. It probably flexes even more because it's not supported on all 4 sides. 

If it were me, I'd get at least a 3 mm if not a tiny bit thicker sheet that is the full length of the tank, then measure and cut if you'd like to have two separate covers for the 2 sides (assuming a center brace is supporting the middle). It should run you around $15-20 

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## vvDO (Oct 18, 2010)

You'll have to custom order tempered glass to fit... can't cut it once its been tempered.


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## Finster (Dec 30, 2009)

What about the corrugated polycarbonate that's used for greenhouses?


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## torque6 (Jun 7, 2008)

We don't have corrugated polycarbonate sheets available locally. Our home depot stores don't carry them. I have only found 1 supplier at the industrial park but they only come in 3 x 3 metres. Abit overkill for a 3FT tank.


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## Nordic (Nov 11, 2003)

Most of the double skinned sheets have ribbing in. You need to cut it so that the ribs go across the short side, then they will self support.


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## Dman911 (Nov 24, 2016)

vvDO said:


> You'll have to custom order tempered glass to fit... can't cut it once its been tempered.
> 
> 
> Sent from my iPhone using Tapatalk


Just wanted to add to this. Your better off with float glass for 2 reasons. 

1. As stated you cannot cut glass once its tempered.

2. If it tempered glass breaks on top of your aquarium you would have a thousand small pieces if glass to dig out, float glass will break in shards and would be much easier to pick out.


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## astex (Aug 13, 2009)

Just put the twinwall sheets on my 180g, and am surprised by how much I like them. Visually I can't see a decrease in light levels.

Like glass, I'm sure the levels will decrease over time as the minerals get deposited from evaporation of my hard water. On the plus side, it will be a lot easier, and cheaper, to replace when they can't be cleaned any more. 

On the other plus, very easy to cut/customize, and all my future tanks will be using this material instead of glass.


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## torque6 (Jun 7, 2008)

I like twinwall sheets for it's rigidity, but they insulate more heat than glass right?


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## jeffkrol (Jun 5, 2013)

Glass transmits 90% of PAR. Twin wall clear polycarbonate transmits 80%..
And yes, they insulate more..


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## BigMek (Dec 6, 2016)

You should be able to order the corrugated polycarbonate sheets from the local Home Depot, even if they don't have them in stock. Or order them from homedepot.com and have them shipped to your local store for pickup. In case you didn't know, there are also end caps for those sheets that fit the corrugations. Those should seal the humidity even better and also support the ends.


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## AndreyT (Apr 28, 2011)

kapoorplastics said:


> The ideal material is acrylic. This material is sturdy, durable, waterproof, and has the same crystal clear transparency as glass.


Acrylic has high thermal expansion coefficient. If the tank is kept at temperature higher than surrounding room temperature (which is normally the case), a simple non-framed acrylic cover will bend - the edges will curl away from the tank. Polycarbonate holds its shape a bit better under small temperature gradient.


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## awesometim1 (Oct 31, 2013)

How about the aqueon Versa tops? They can be cut in the back and they're glass on where the light passes through. I ordered mine from dr fosters and smith(cheap) and it's coming in today. I'll let you know how it looks


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## SingAlongWithTsing (Jun 11, 2015)

awesometim1 said:


> How about the aqueon Versa tops? They can be cut in the back and they're glass on where the light passes through. I ordered mine from dr fosters and smith(cheap) and it's coming in today. I'll let you know how it looks
> 
> 
> Sent from my iPhone using Tapatalk


only problem with the versa tops is the black hinge in the middle, might cut down your par depending on what type of light you're using. if you're using Leds i dont see it being much of a problem though


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## awesometim1 (Oct 31, 2013)

Here is a picture. 


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## jeffkrol (Jun 5, 2013)

Black/brown hinge is annoying (at least on my tanks) if in the middle.
Just modified my 40 hood by cutting the hinge in pieces..leaving clear space be tween the 3.

you can buy white/clear hinge material.. not sure why they insist on it.. must have a lifetime purchase order from the manuf.. 
to be honest.. its stupid.


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## Dman911 (Nov 24, 2016)

If you want cheap lids phone a window and door company and ask them if you can come get some used glass windows, then cut your own. There are lots of ways to make hinges or you can buy them clear like Jeff pointed out. Hell you can by thin clear vinyl and just silicone a couple strips to each side. I used to get unlimited amounts of 6mm glass from these companies as they just throw them out and built more tanks and sumps than I can count. You would be surprised how new old windows look after a quick wipe and they never have scratches.

Dan


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