Need help with multiple tank setup

[1stNoel]

Hello Reefers,

I currently added 3 lowboy frag tanks to my 300 gallon display tank. I also want to add a 50 gallon tank (that used to be my QT tank) to this setup.

Here's the issue:
I'm able to plumb outbound water from all 5 tanks to the sump...but I could only plumb incoming water to 4 of the tanks, so I'm considering creating a gravity-fed overflow from the 300 to the 50 gallon QT tank.

Note that both of these tanks are HOB-overflow (i.e. not drilled); the lowboys are all drilled.

I thought of creating a U-tube out of PVC, with the PVC (from the 300) going just below the water-line so it would break syphon and not overflow the 50 (in case the 50's overflow-to-the-sump ever lost syphon). I also wanted to add a float valve for redundancy, but am not sure how to incorporate it.

Any thoughts or suggestions on the setup are appreciated.

Thanks,
Noel

 

[Daddy-o]

I run 4 tanks plumbed to the same sump with only 2 return pumps. I pump up to the two highest and they gravity overflow to the other 2 tanks which overflow into sump

 

[1stNoel]

I run 4 tanks plumbed to the same sump with only 2 return pumps. I pump up to the two highest and they gravity overflow to the other 2 tanks which overflow into sump

Are all of your tanks drilled? 2 of my 5 are hang-on-back overflows, and drilling them is not an option. I just want to be sure I guard against a water spill (as best as possible given the constraints).

 

[Daddy-o]

2 drilled and 2 CPR overflow boxes. They are in my garage. The CPR boxes have only overflowed 5-6 times in 2 years. I would never run an overflow box on a reef in my house

 

[Brett S]

I thought of creating a U-tube out of PVC, with the PVC (from the 300) going just below the water-line so it would break syphon and not overflow the 50 (in case the 50's overflow-to-the-sump ever lost syphon). I also wanted to add a float valve for redundancy, but am not sure how to incorporate it.

I don’t think this would work. If the 50’s overflow lost it’s siphon then it wouldn’t affect the water line in the 300... the 300 would keep draining into the 50 and the 50 would overflow no matter what. And keeping the U-Tube close to the water line just sounds dangerous do me. If the U-Tube gets too much air in it you’ll lose the siphon between the 300 and the 50 and the 300 could overflow.

I’m not sure you have any options for a float valve. At least I’m not aware of any float valves that would work with the pipe sizes and volumes of water that we are talking about. If you have an apex or another controller you could use a float switch that would turn off your return pump if the water level got too high.

 

[Daddy-o]

Also, If you plumb the QT to the display, are you not defeating the whole idea of a QT?

 

[Brett S]

Also, If you plumb the QT to the display, are you not defeating the whole idea of a QT?

I think it was formerly a QT but is now being repurposed for something else.

 

[1stNoel]

I don’t think this would work. If the 50’s overflow lost it’s siphon then it wouldn’t affect the water line in the 300... the 300 would keep draining into the 50 and the 50 would overflow no matter what. And keeping the U-Tube close to the water line just sounds dangerous do me. If the U-Tube gets too much air in it you’ll lose the siphon between the 300 and the 50 and the 300 could overflow.

I’m not sure you have any options for a float valve. At least I’m not aware of any float valves that would work with the pipe sizes and volumes of water that we are talking about. If you have an apex or another controller you could use a float switch that would turn off your return pump if the water level got too high.

Thank you! This is exactly why I asked the question. So, based on your feedback, having the 300 overflow into the 50 is a no-go.

As far as the 300 goes, the waterline is set about 4 inches lower than normal (just kind of worked out that way, and I prefer the tank shallower anyway)...so if the entire sump dumped into it, it wouldn't even be close to overflowing. So no worries there.

As far as the 50 goes, I will cycle in some "fresh water" from the other tanks during my weekly maintenance. Since any excess flows back into the sump, it's an easy thing to do.