# Using plexiglass as a tank lid thoughts and concerns



## Imaginary1226 (Jul 27, 2010)

I think it also depends on how thick it is, it wont warp as much if it's thick of course. It would probably block some light as well though. I would also think it would be harder to get buildup off of. I personally like good ol glass.


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## Hardy85 (May 3, 2013)

I've seen lexan as a replacement that doesn't bend, warp or discolor over time. It does cost a bunch per sheet, but if you are looking to make multiple lids and have the means to cut it, it'd be worth it


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## rdmustang1 (Oct 20, 2013)

Hardy85 said:


> I've seen lexan as a replacement that doesn't bend, warp or discolor over time. It does cost a bunch per sheet, but if you are looking to make multiple lids and have the means to cut it, it'd be worth it


My tank builder (Jason Gregory) built me a Lexan lid for my acrylic tank. He said Lexan is much better than acrylic as you won't have to keep flipping it. While it does seem to keep a tiny small bend in it it's worked great so far (~4 weeks). Mine is 1/4" Lexan on a 60"x30" top.


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## Bushkill (Feb 15, 2012)

I don't think you'll find Lexan at a box store. If my fuzzy memory serves me right, they only sell acrylic sheet in two thicknesses. As mentioned, Lexan is more expensive and acrylic isn't cheap either. Acrylic will bend. Severely. And just doesn't work as a tank cover. I've never used Lexan so I can't comment on using it other than its' cost. I can't be specific as to the reason, but it always warps away from the water. So if it's a moisture issue, it curls away from the water. I've never put a light fixture over acrylic so I can 't say if it would curl in the other direction.

Why are you considering acrylic / lexan instead of glass?


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## PlantedRich (Jul 21, 2010)

Even 1/4 thick plex was no good for me. Since it did not work, I found a canopy to be a good option that works better to hide the ugly on top of tanks. With a canopy, I can get air without jumpers and use all kinds of ugly cheap lights since they are out of sight. An open top reduces my worry about EOTD.


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## Bushkill (Feb 15, 2012)

Just a word of caution on using glass from Lowe's or HD: It's window pane glass, and just as thin as thin can be. I know I tend to overbuild, but just keep in mind that this stuff won't hold up to much pressure or any sort of shock, and most important remember to sand down the sharp edges which Lowe's won't do.


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## thelub (Jan 4, 2013)

The glass at the hardware stores aren't even window pane glass. Its picture frame glass. Super thin and not very strong at all. 

I mentioned in another similar thread that I've posted ads on craiglist requesting broken tanks so I can use the glass for tops and other projects. I've got tanks for free with this ad. A cheap glass score tool and some sandpaper and you got yourself almost free tops. They'll be better than plexi and you won't have the hassle of the stuff warping and getting fugly on you.


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## ZillionGuppies (Jan 21, 2014)

Lexan is just a brand name for polycarbonate. Polycarbonate is the generic industry term. Similarly, plexiglass is a brand name for acrylic.

If you can find a local plastic supply place you should be able to ask for polycarbonate. I've even seen some local glass shops selling plastics. I have seen polycarbonate being sold at Lowe's or Home Depot under some name other than "Lexan"

If you really can't get it locally then McMaster Carr will ship it to you. Other options may be TAP Plastics and E-bay.

For me personally, I wouldn't put anything glass or plastic between my lights and my tank.


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## Bushkill (Feb 15, 2012)

thelub said:


> The glass at the hardware stores aren't even window pane glass. Its picture frame glass. Super thin and not very strong at all.
> 
> I mentioned in another similar thread that I've posted ads on craiglist requesting broken tanks so I can use the glass for tops and other projects. I've got tanks for free with this ad. A cheap glass score tool and some sandpaper and you got yourself almost free tops. They'll be better than plexi and you won't have the hassle of the stuff warping and getting fugly on you.


Man after my own heart. Agree on every count. I've "inherited" broken tanks and it's much cheaper than buying 3/16 or 1/4" glass. Having 22+ tanks, I've got glass covers over almost all of them this way. I also use small glass mosaic wall tiles to silicone on handles.

At those thicknesses, you'd be amazed at the shocks it can absorb safely. A cinderblock, maybe not.

If you have little guys running around the house or a rambunctious cat, I may change my mind. The cat won't fall through, but it may bring things down onto it.....like a cinderblock, lol!


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## tattooedfool83 (Mar 15, 2013)

I have glass over a few tanks from lowes and never had one break, although it is wicked thin. But for what people are saying as far as cost and such of lexon and other products I mine as well buy a glass lid.


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## sowNreap (Jun 10, 2012)

I also just use the thin glass from Lowe's. I don't have kids or other pets and I'm careful with them. I didn't make fancy tops, the glass just rest on top of the tank. I lift it up to feed & take them off when working in the tank. I use them to keep my heaters from working so hard. My basement gets down to about 55 degrees in winter & in summer most it gets is 75. It's nothing fancy so not for everyone. Never had any problems or breakage .. BUT what works for me might not work for anyone else. 

I also got a piece of acrylic from Lowe's .. was a scrap piece so thought I'd try it since I needed something at least 19" long but only 5" wide. It DOES warp. I turn it over every few days & until it warps the other way. Or take it off for a couple hours & it will straighten back out. If I end up keeping that tank I'll probably get glass for it.


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## jmsaltfish797 (Oct 27, 2012)

the plexi warps due to the temperature difference between the air under it and the air outside of the tank. you can flip it or just go with glass. if you go to lowes ask for double strength glass. if you dont ask for it specifically they will give you the super thin stuff, which is made for picture frames, not fish tanks. its not that expensive to get a piece of 1/4 in from a glass shop either. plexi is much more expensive compared to glass.


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## DogFish (Jul 16, 2011)

There is a shop on ebay, the man is in Indiana. He will make a one or two cuts for free on his Lexan sheets. I've bought from him several times. Very nice guy. He also sells the glue but that has to be shipped separately as it's hasmat.

I 've been dumpster diving for old aquariums to learn/practice my glass cutting skills. As thelub posted $7 glass cutter, sand paper & a straight edge, your ready. I use 5 round 100gt. sanding disc paper because it has a heavy paper backing. It last longer and is a little safer to use.

I've learned that 3/8s glass can not be cut less that 4" if you are good, 8" if you are a beginner.


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## Bushkill (Feb 15, 2012)

SowNreap brings up a really important point about using glass: It keeps your tank warmer. It does a much better job of containing heat in the tank, compared to curled pieces of acrylic this time of year. And then there's the evaporation issue too. Keep a tank at 75-80 degress in a room with an ambient temp. of 60-65 and evaporation becomes a big deal.

DogFish also hits an important point: 3/16" is easy to cut; 1/4" isn't too bad but 5/16" and up is really tough with the cutters most have available to them. A long time ago, I got a whole PILE of glass shelving for free. It was all 3/8". I was all full of myself after all the projects I'd finished using 1/4" scraps. Let's just say that I wasn't so full of myself after I butchered a bunch of those 3/8" shelves. So if you find/are given scraps of really thick material, try and work with it as it is and save yourself the headaches, lol!


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## TECKSPEED (Jan 2, 2013)

@tattooedfool83 I used a piece of plexiglass over my 20 gallon high tank, I find what happens is that with the light on your fine, but as soon as some water touches the plexiglass and makes calcium deposits on it then your par is reduced a little bit. In my experience the plexiglass droops in the center sometimes causing it to contact the water, believe me I wanna get glass cut but was trying to save money with plexiglass, I'd stay with glass from home Depot or Lowes. Just my opinion, you'll find out setups similar I also use a Finnex fixture. 

Sent from my LG-E980 using Tapatalk


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## cownose-ray (Sep 28, 2013)

Plexiglass warped for me even when I didn't have a light on the tank.


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## roadmaster (Nov 5, 2009)

I'm thinking of going to local galss company that repair's broken store front window's and asking if they have any scrap pieces.
These should be fairly thick glass, and hopefully they won't be asking much for the scrap.
Maybe they might even cut a piece for me.


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## Bushkill (Feb 15, 2012)

roadmaster said:


> I'm thinking of going to local galss company that repair's broken store front window's and asking if they have any scrap pieces.
> These should be fairly thick glass, and hopefully they won't be asking much for the scrap.
> Maybe they might even cut a piece for me.


Worth a shot. What you don't ask for, you don't get.


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## ZillionGuppies (Jan 21, 2014)

I hate to harp on this but what kind of light transmission are you getting with thicker (1/4" and up) glass? I don't have a light meeter so I can't do this experiment for myself. I'll bet someone reading this thread does have a light meter and could do a simple test to see how much the light level is reduced when various different thicknesses of glass and plastic are placed between a light and light meter.

As aquarists we tend to spend a lot of resources on getting light into our tanks. If it were me I would want to know how much light that pane of glass was going to block. In the long run it may actually be cost effective to go with low iron glass or another material to minimize light loss.


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## Bushkill (Feb 15, 2012)

ZillionGuppies said:


> I hate to harp on this but what kind of light transmission are you getting with thicker (1/4" and up) glass? I don't have a light meeter so I can't do this experiment for myself. I'll bet someone reading this thread does have a light meter and could do a simple test to see how much the light level is reduced when various different thicknesses of glass and plastic are placed between a light and light meter.
> 
> As aquarists we tend to spend a lot of resources on getting light into our tanks. If it were me I would want to know how much light that pane of glass was going to block. In the long run it may actually be cost effective to go with low iron glass or another material to minimize light loss.


You raise an interesting and perfectly valid question. And since I tend to fly by the seat of my cheapskate pants, I would just say that finding low-iron glass of any thickness cut to specific dimensions that would make this a cheap date may be tough. So that if there is in fact an unacceptable loss of light penetration that would be an issue for me, I would opt for more light before I try and find a glass shop to cut a small (by their standards) piece of low-iron glass. 

Also, consider that condensation will collect on the bottom of any form of glass and leave behind deposits and various films. 

If a particular settup has extremely high light demands, I think you'll find a good number of those to be run open-topped and simply deal with evaporation either manually or with an ATO mechanism.


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## tattooedfool83 (Mar 15, 2013)

TECKSPEED said:


> @tattooedfool83 I used a piece of plexiglass over my 20 gallon high tank, I find what happens is that with the light on your fine, but as soon as some water touches the plexiglass and makes calcium deposits on it then your par is reduced a little bit. In my experience the plexiglass droops in the center sometimes causing it to contact the water, believe me I wanna get glass cut but was trying to save money with plexiglass, I'd stay with glass from home Depot or Lowes. Just my opinion, you'll find out setups similar I also use a Finnex fixture.
> 
> Sent from my LG-E980 using Tapatalk



Honestly i just ended up buying a versa top, i went to my lfs where i get a 20% discount anyways. my homes tanks the ones with tops are all lowes glass, so i was leaning towards that. But i have people with kids that come into my office and dont wanna take the chance of the glass breaking or something. so the versa top it was, think i spent $15 on it. Should have my finnex fixture tomorrow then substrate on saturday and ill be good to go to set it up sunday. What ill do is prolly remove the plastic piece that holds the two pieces of the versa top together so its just purely glass and no obstructions.


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## TECKSPEED (Jan 2, 2013)

tattooedfool83 said:


> Honestly i just ended up buying a versa top, i went to my lfs where i get a 20% discount anyways. my homes tanks the ones with tops are all lowes glass, so i was leaning towards that. But i have people with kids that come into my office and dont wanna take the chance of the glass breaking or something. so the versa top it was, think i spent $15 on it. Should have my finnex fixture tomorrow then substrate on saturday and ill be good to go to set it up sunday. What ill do is prolly remove the plastic piece that holds the two pieces of the versa top together so its just purely glass and no obstructions.


That's what I do with my versa tops and keep a little space at the back for heater cords etc. 

Sent from my LG-E980 using Tapatalk


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## rdmustang1 (Oct 20, 2013)

Not sure what Lexan normally goes for but my tank builder cut me a custom 54"x24" Lexan lid for $60.


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## tattooedfool83 (Mar 15, 2013)

TECKSPEED said:


> That's what I do with my versa tops and keep a little space at the back for heater cords etc.
> 
> Sent from my LG-E980 using Tapatalk



Yeah exactly. Enough space for heater cord and intake/outflow pipes.


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## DogFish (Jul 16, 2011)

Bushkill said:


> DogFish also hits an important point: 3/16" is easy to cut; 1/4" isn't too bad but 5/16" and up is really tough with the cutters most have available to them. A long time ago, I got a whole PILE of glass shelving for free. It was all 3/8". I was all full of myself after all the projects I'd finished using 1/4" scraps. Let's just say that I wasn't so full of myself after I butchered a bunch of those 3/8" shelves. So if you find/are given scraps of really thick material, try and work with it as it is and save yourself the headaches, lol!


My last project a glass "dome" for my Aquaponic system:


This was from the front pane of a very old 3/8" 55 ga. tank I found in the trash. What you don't see is how I slaughtered the back, sides and bottom panes before I manage to make 3 good cuts :redface::redface::redface:


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## shadow83 (Jul 20, 2018)

*Plexi & lexan?*

How is plexi or lexan at maintaining clarity?


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