drilling a established tank?

I drilled an established tank. It was easy. I used a glass holes.com overflow kit. Drain a quarter of the water out. Have someone hold a Dixie cup over the inside of the tank. This will catch all of the glass shards from getting in the tank. Then drill carefully, frequently dip the bit into a cup of water to cool it off and lubricate the bit.

If you must drill from inside the tank... Cut the bottom of the Dixie cup out and insert the drill through the bottom of the cup and proceed to drill slowly. You can't use a lot of water this way... And you need a towel underneath the cup when you try to remove it. It would be a good idea to use plumbers putty to seal the dixie cup against the glass.

It is not much different than drilling an empty tank.

Hang-on overflows suck. Especially when they lose siphon and you have 30+ gallons on your floor.
Good luck!

 

You can do it very easily.


Install the weir(?) (the wall that is normally placed for the overflow wall) in and go ahead and seal it. Drain water from the side where you'll be drilling, wala, that part will be water free. Cut the holes in the overflow wall once everything is setup or remove it and cut it down and cut the holes in it.

 

I've used an Eshopps overflow on the 92 for a few years.

 

How do you seal the weir if the tank has water and substrate??? Am I missing something???