Drilling Established Tank
 

I have an established 120 gallon reef tank for 5 years with a CPR overflow which uses an airlifter to maintain the siphoning.

I'm getting a VERY tired of the airlifter failure! Siphoning stops, the return pump continues to pump water out of the sump into the main tank....sensors in the sump senses a low water condition and my resovier pumps water into the sump........WET BASEMENT! :help:

I'd like to drill the tank to install an overflow into my established tank. Has anyone attempted this on this forum? I can empty approximately 40-50% of the water. Will this work??

Thanks!

run the air line into a powerhead, that way when the powerhead quits, at least you won't lose your siphon.

drilling the tank shouldn't be an issue if your sure the glass is not tempered, and your sure you can do it. put a rag on the inside to catch any glass dust. you'll have to trickle water over your cut and have a way to catch it.

I'm a pretty reckless person, and I'm not sure I'd drill a tank that had water in it. If it went bad, it would be real bad :)

I've considered it but haven't tried it ...yet, here's a video of someone else doing it though.

http://www.youtube.com/user/DrGonzoR.../1/OlaOl-dBniI

I've done it before with a 150 g. Worked well. Had the overflow built ahead of time. Then drilled it with it 1/3 full. Then silicones the overflow in. Refilled the tank up to the level of the new overflow, then ran it with powerheads while the silicone cured overnight, then refilled it after plumbing the new
Overflow. Hope this helps.

I've never done a tank with water in it but I have drilled 1 unsuccessful hole, then had the glass re cut and drilled 3 successfull holes.

I bought my glass hole saw from princess auto. The hole that cracked the glass... I drilled with the hole saw and the centre drill bit that came with the mandrell http://www.princessauto.com/workshop...ories/list-all

The drill bit was not turning perfectly level, once the centre bit broke through, the glass cracked.

Second time round I removed the centre drill bit, and used a piece of plywood with 3 pre-drilled holes the size and place i wanted to drill on the glass. I also had a piece of plywood on the inside to help prevent chipping and "busting" through on the other side. I clamped them together on either side of the glass (already siliconed in place in the aquarium) I drilled 3 holes in a row like this with no issue. I also had a cold water hose trickling on the spot I was drilling the whole time.

and if tempered

Wingedfish,

thanks for the advice. I will try the powerhead method. The only place will be in my sump. do you foresee any issues running the venturi tube so long?

once again, thank you

Would you be drilling the side or the back? Both can be done with a partially full tank but drilling the side is much safer. Done this a few times without ever having an issue, the thicker the glass the less likely you'll crack it. I've only ever cracked 6mm or smaller, never cracked 10mm or larger.

I'm still trying to decide on whether or not to drill. Thinking its a little on the risky side. When I decided, I will drilling the back corners.

I have a 120 gallon Hagen tank. Glass is prob around 10mm