Can anyone help drill an overflow for a tank currently filled. Will obviously pay

I currently have a 210 gallon standard tank that I want to use a sump with instead of canister filters. I heard horror stories from using hob overflows. The only problem is that the tank is filled which I can drain to a level where it can be drilled. There isn’t enough room on the back of the tank because of how close it is to the wall. Maybe 7 inches. So i was thinking of drilling it to the side of the tank which I don’t care. If anyone here can do that for me please let me know. I’m located in little egg harbor nj

This is not a good idea on many levels. I would not drill a tank vertically (although I've done it). I would not drill a filled tank, even partially. Drain it, set it on the side, drill it.

Test it to make sure it's not temp. glass first.

I have drilled lots of tanks. Let’s say 80 or so holes. While easier on thicker tanks….

We need to keep a constant flow to water to both clean out the debris while drilling and probably more importantly keep the glass cool.

That does entail keeping on the side.

While it can physically possibly be done, there are lots of variables.
The pressure being exerted on the tank from the filled portion is most concerning…

I like to gamble and even I would not attempt.

If you do…
1. Confirm not tempered as Diana mentioned.
2. Make sure insurance is up to date
3. Prepare for the worst. Several large rubbermaids and mixed Ed warm saltwater on hand. Possibly leads on a replacement tank-even if smaller.
Have multiple shop vacs, towels andand fans at the ready.

Good luck.

Maybe record you ENTIRE process as a learning lesson, how to, possibly to deter or encourage others… or for entertainment.

I have an Eshoppes hob overflow box. Going on 6 years now without a single issue. It’s never broken siphon and or failed to resume running after a power outage. It only requires a few inches between the tank and wall. I’d very much recommend getting two of them rather than risk drilling.