Overflow Box Questions(again)

Well because of the sticker on the bottom saying "do not drill" and since it's an old tank many people (on here and at a couple of my lfs's) have said it's not worth risking.

 

Thanks Mike,
That's what I've really been waiting to hear.

 

If the glass is tempered you will not be able to drill it. The tank is almost definitely tempered glass on the bottom and most likely not tempered on the sides. How to tell if it's tempered - How to tell if glass is tempered. - Saltcity Reef Forums

If it's not tempered, I'd go with drilling the tank. I've had both overflows and drilled tanks and drilled are definitely the way to go if you can. Overflows need cleaning and they do carry the risk of the siphon stopping and floods. You can drill the Utube and crazy glue/silicone a nipple to the top from a cheap airstone and connect airline tubing and an aqualifter to help keep the siphon going. If you go with an overflow, I'd recommend the aqualifter. Avoid the cpr overflow boxes. They look great in design, but are a royal pain to clean. The U tube type are better.

Once you drill a tank though, you will never use overflows again. It is super easy to do. Search on You Tube for videos. I've drilled a half dozen tanks now and never broke one yet. The last one I drilled was my old 75 gallon display tank to convert it into a refugium.

Even if you don't drill this one, you should still look into how it is done. Once you know how to do it, it comes in handy all over the place in this hobby.

 

The only way to do it is to drill it IMO. I'm paranoid about the overflow boxes, even if you're not it's just one more piece of equipment that you have to clean/maintain.
Just have a return pump that does about 400-600gph (after head loss) and you'll be fine.