What size return pump for Oceanic 90 gallon tech series?

I had a 700gph mag drive pump but it was a little too big and the water went down about an inch and a half in about an hour or 2. I have a 630gph pump but don't want to try it because i won't be able to return this one if i do. Does anyone know what size return you need for an oceanic 90 gallon tech series? Thank you!

(I'm not running it to anything except the 2 bulkheads that return the water to the tank) It goes up in a T and goes to the 2 bulkheads.

 

I would get somewhere in the 900+ gph.. Mag 9.5 is a good pump, maybe even something bigger if youre going to run other stuff off of it..

 

+1 on the mag9.5.... you could even go with a mag 12 if you woant more gusto

 

I'm running an 1800 on a 90 and built a manifold to feed my reactors off of it then have a ball valve in place between the pump/return nozzle to throttle it back a little

 

for some reason even with the 700gph pump the water level in the sump gets lower and lower so i think that i need a smaller return pump maybe around 600gph?

 

Does the water level in your display tank start to get higher and higher?

Maybe you could put a Tee in your return line from the pump and recirculate some of the flow back to your sump. Put a gate valve on it so you can dial in the flow you need.

 

No I don't think the display is getting higher, it just seems to be that the area in the sump where the return pump is gets lower, I put a piece of masking tape on the sump where the pump is and it moved about an inch or 2 in 6 or so hours. I thought about the T and gate valve but i couldn't find a gate valve that would connect to the T and the flexible tubing.

 

add more water to your system..

 

I'm pretty new at this.. but if you are losing water faster than just losses from evaporation, then the water has to be going somewhere. I'm just wondering if your return pump flow is greater than your drain flow back to the sump.

Gate valves are a little harder to find than ball valves. You tried looking online? If not, a ball valve would work, but it doesn't allow for as much precision.

 

Sounds like your return section is too small.
My return section can drop 8 gallons or more before I have to add water but even that was a pain so I added an auto topoff device.

A Mag 7 or 9.5 are both good sizes but I hate Mag pumps in general due to noise, heat and vibration issues so much prefer and highly recommend an Ocean Runner 250 or 3500 ( I use 3500's myself in my 100G system) or an Eheim 1260 or 1262. All are much better pumps, use less energy, create less neat and are quieter in operation. I recently sold all 4 of the mag pumps I owned, from a 2 up to a 9.5, because of all those issues.

Are you restricting either the overflow or return pump in any way? The tank and sump should balance themselves out in just a few minutes and stay at that level minus any evaporation which will be seen in the sumps return chamber. How big is your return section?