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Drill back of tank or purchase/DIY overflow

Ariel S

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I have a 40 gallon breeder and I want to add a sump underneath. I'm trying to decide the best/ easiest/ and pros and cons of different methods.  

I don't really have the skill to drill the back panel but I can probably beg someone to do it for me or do it very carefully.

I've also watched numerous videos of drilling tanks and plumbing and overflows you can buy and DIY instead of drilling. Any suggestions? tips? I've watched numerous videos on youtube and just cant decide what is best for me. I know that marine depot sells some, but those seem to all be geared towards reef tanks. 


This is a freshwater tank by the way. 

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Drilling glass isn't as scary as you think, or at least I thought it would be. Just go slow and barely put pressure on the drill. Making sure it's not tempered is important, if you look at the tank with polarized sunglasses and see straight lines, the glass is tempered. There are YouTube videos showing what you'd expect to see. 

A HOB overflow won't care if it's fresh or saltwater. I think those are sometimes discouraged because of the risk flooding if they lose siphon and overflow. 

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The HOB overflows are notorious for failing or overflowing. But doesn't mean they won't work (also way more expensive then glass drilling)

I'm always for drilling tanks just as it's sleeker and less failure rate (not gone but less)

It's not as scary as it seems but feel free to research a bit. Plus very few if any tanks are tempered anymore because they know people drill them. 

The only really common ones are tempered on the bottom Pane not the sides. But it's always worth checking. 

There is also a few ways to check. Polorized sun glasses are one. And their are a few others. 

I went into drilling a tank pretty blind with cheap online drill bits and I had a lot of success. It is way less scary than you think. Get the gear together take a breath and just do it! 

If you can get a spare bit of glass or maybe a broken tank or a free or cheap one you think you might like drilled and try it out if the 40 Gallon is more valuable. 

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14 minutes ago, Ariel S said:

Thank you! To drill it is!

You can make a template for your glass drill but using a wood hole saw and a thick piece of plywood. 

This is a good article if you haven't read it already. 


Any time you drill a hole in glass there is a risk of failure. We will give advice as to best practices for...


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