FreshWaterFun

So I am going to be coming across a 120 gallon tank soon, and slowly, very slowly I will be creating myself a nice saltwater aquarium. I have no idea if the tank is acrylic or glass. My question though is this, is it too dangerous to try to drill the tank if it is glass? I really want to drill it so i dont have to use an overflow box to do the whole sump process, so any imput would be greatly appreciated. Thank you in advance.

Peterpiper

I would have it drilled as you dont want the overflow,
You will always run the risk of cracking the glass, but if you do crack it, you can get it replaced with a drilled one.

Wyphy

There are some videos on YouTube about drilling aquariums, and they are pretty informative. Especially the videos by LimpitsReef (Reef Tank DIY Sump video, 1 or 2, I forget) and the one by BulkReefSupplyCom.

In general, it doesn't look that hard, you just need to be aware of what you're doing and have the right tools.

You have to have the proper bit, which is a diamond coated hole saw/bit.
I've seen it said that they were available on ePray for relatively cheap, but never looked myself. Cheap tool places like Harbor Freight may also be an option.

You also have to make sure the glass isn't tempered. Tempered glass will shatter if drilled. You can find a few videos of that too.
You may need to call the manufacturer to find out for sure, but most frequently it's just the bottom glass that's tempered.

cerianthus

Have drilled many tempered glass even though were told cant. Used Diamond Tip Bit (cost me $100/pc about 20 yrs ago). Need Steady hand though. 120 G should be plate glass and thick but still can crack....
Need Putty to make o-ring which will hold AntiFreeze to keep the blade somewhat cooled.

Make sure to wear goggle and have powered Drill (not Battery) and STEADY Hand.

Could have Insured Glass Cutter to drill it for you and might as well build/ cut glass overflow Box (panels) with teeth on top just life Reef Ready Overflow. Should have two overflow for 120G, one on each corner. P/U proper size bulkheads so can drill right size holes. ususlayy 1" bulkhead for drain and 3/4" bulkhead for returns. LMK if need diagram.

FreshWaterFun

A friend of mine has had saltwater tanks for a while. He actually is buying my 125 gallon fishtank from me soon. He started with a 40 gallon tank that he drilled himself and is now currently using a 90 gallon also which he drilled himself so i might have him do the drilling. Im getting married next year so most of my saving will be going to that, but some of my money will be going to set up this 120 gallon beast of a tank. I just want to do it right and make good home for my future fish. For now though i will just work with my 30gallon saltwater tank and be happy untill the new one is set up. Thank you for all the advice and tips.

au01st

What do people have against overflow boxes? When set up properly there is virtually no risk of overflowing or running dry. I wouldn't bother drilling a tank, I'd just run dual overflows. That said, if I was to drill, I'd use a Calfo style overflow that runs along the back length of the tank and sticks out just a few inches, rather than ones that run the whole height of the tank in each corner. Check em out.

lew2000

One thing, if you know the manufacturer of your tank get the specs - large manufactured tanks tend to use tempered glass as the bottom plate. Actually i would recomend that you take it to a glass shop (that actually knows what they are doing)for drilling - if you can lug it around to one - or as you said have your friend do it. With tempered glass there is no forgiveness if a mistake is made in applying perssue ora less than sharp bit.

aquaman05

I would like to see a diagram if its not a problem