Retrofitting a closed loop in a running tank

[DaveS]

I have my acrylic tank and it's fully established. I'm a little unhappy with the plumbing and I'm considering making some changes. Things I'd like to do include adding a closed loop and maybe moving my returns. I'd like to avoid breaking the tank down and draining it to drill the holes as it seems like such a hassle and mess. As crazy as it sounds, has anyone come up with ways to drill holes in tanks while they still have water? Maybe some kind of airlock type container over gets put inside the tank where the hole will be drilled. You'd leak some water but not a ton. I dunno, just wondering out loud...

[dbartco]

could always create a siphon draw over the edge of the tank, put the returns where you want. Have multiple, just put in some valves...

[Jon Lazar]

Dave,

 

I added a closed loop to my acrylic tank while it was running by drilling a hole through the top and running a pipe straight down into the water. This pipe served as the pump intake, and I positioned the pipe behind rockwork and corals so it was hard to see.

 

If you want to put the bulkhead in the back wall of the tank instead of the top, you can drain your tank water level down long enough to make the hole and do your plumbing, then refill the tank. The plastic shavings aren't going to hurt anything, and I've never had a problem with corals being out of water for an hour. I didn't have enough room behind my tank to go that route.

 

Jon

 

I have my acrylic tank and it's fully established. I'm a little unhappy with the plumbing and I'm considering making some changes. Things I'd like to do include adding a closed loop and maybe moving my returns. I'd like to avoid breaking the tank down and draining it to drill the holes as it seems like such a hassle and mess. As crazy as it sounds, has anyone come up with ways to drill holes in tanks while they still have water? Maybe some kind of airlock type container over gets put inside the tank where the hole will be drilled. You'd leak some water but not a ton. I dunno, just wondering out loud...