DIY Sliding Glass Tank Lid

One of the fishkeeping hobby’s little annoyances is the problem of evaporation.  It may just be me, but it irritates me to have to top off a tank in between water changes.  Evaporation becomes more than a nuisance, however, when you are running — or planning to run — more tanks than are necessarily good for your sanity.  The moisture coming off a collection of tanks can potentially be a real threat to your home and health.

Apparently, one way to control evaporation is to use glass lids.  I’ve read this several times, but can’t vouch for it, since glass lids are hard to find locally and it just hasn’t been in my budget to have them shipped… but, as it turns out, a little hard work can produce a super-cheap sliding glass lid using materials from your local hardware store!

First, let me say that this DIY project isn’t my own brainchild.  I never would have known how to do this if not for a thread on The Planted Tank. I’ve been excited about trying it for a long time, and I finally got around to it.

Click past the cut to watch me make my very first sliding glass aquarium lid and to read my thoughts on the process!


  • tileboard trim (I paid $2.67 but used less than half)
  • window replacement glass ($6.48, used/wasted about 2/3)
  • glass cutting kit ($12.98, but just the glass cutter — $6.96 — is enough, apparently)
  • T-square or other straightedge (you already own one, right?)
  • something thick and straight to break the glass across… a 2×4 is somewhat overkill

Photos of the lid on the tank (it’s fogged up a good bit, but just think — all that condensation would be floating around in the room as humidity):

Obviously, you can have the glass cut for you, but since the store I went to didn’t offer that service, I decided to be adventurous and do it myself.  It wasn’t bad — I’ll do it again.

The first step is knowing exactly what size to cut the glass.  Measure the inside lip of the tank rim carefully.  I imagine there’s nothing worse than having glass just a shade too wide to fit.  Keep in mind that the tileboard trim, although thin, will take up a little space.

You probably want the two halves of the lid to overlap a little in the center, so cut each one a little more than half the total dimension of the tank.  I left a little more overlap than I wanted, but I’m okay with that.  It would matter more if the lid was meant to open front-to-back instead of side-to-side, because it would limit access to the tank more.

The cutting tool is supposed to be used with oil (mineral oil would work fine), but there were too many warning labels on the bottle that came with the kit, so I skipped it. It worked well enough.  Someday I’ll try cutting glass using the oil just to see what I’m missing out on.

The cutter package warns not to use too much pressure on the glass; I overcompensated and didn’t put enough pressure.  Practice will make perfect, I guess.

In the video I break the glass by putting it on top of a straightedge so that the score line is right over the edge, then pressing down until the glass snaps.  My wife suggested later that I should put the glass under the straightedge and pull up.  I’m going to try that next time and see if it works better.

On the first (and biggest) cut, I end up using a 2×4 — it was the handiest edge that was both long enough for the glass and thick enough to bend the glass to the breaking point.  Obviously, you probably want something a little less clumsy. On a shorter cut, I was able to use the thick part of my T-square.

I didn’t want to use the workbench edge because little shards and slivers of glass get left behind.  I didn’t want them in the floor.

Speaking of longer and shorter cuts:  the shorter the cut, the easier it is.  Don’t overcomplicate things by trying long cuts, at least not until you get more experience than I’ve got.

To make a long story short: the video shows the process better than I could explain it.  I ended up wasting a lot of glass making up for bad cuts (not on the video), but I think with a little more practice, I’ll get more efficient.  I’ve got a lot of 10-gallon tanks that need lids, so I’ll do all of those before tackling the 55-gallon tank.  By that point, I think I’ll be pretty comfortable with it.  

Side note: check out the prices on Drs. Foster and Smith — I didn’t save that much money on one 10-gallon tank, true, but by the time I have 8 or 10 tanks that size set up, the savings will add up. (I’m not including the price of the cutting kit in my total cost estimate, since I can use it on multiple projects.  Then again, we’re not factoring in the website’s shipping charges, either…)  More to the point, check out the prices on 48-inch glass tops!  I expect I’ll be able to DIY a lid for my 48-inch 55-gallon tank for about $15, if I keep waste to a minimum.

Be careful: All DIY projects involve some level of risk. Use appropriate safety measures when attempting any do-it-yourself project, especially projects involving electrical apparatus. is not responsible for injuries or damages resulting from unsafe projects. Have a nice day!