Sump info

Im thinking about building a sump to be linked between both my tanks. The more I think about it the more I realize I really dont understand how the overflow and returns work. I would be using HOB overflows on both tanks. How does the pump pump enough water into the DT to keep up with the water overflowing and how does the pump keep up with the overflow?

 

Actually, the pump doesn't keep up with the overflow, the overflow keeps up with the pump. It can't overflow more than the pump puts in the tank. It will run out of water
The tank can only drain what you put into it. And it will drain what you put into it. Whether down the drain or into the floor. If the overflow boxes can handle the water flow you are putting into the tank then the flowrate issues take care of themselves.
PumpA pumps X gallons into TankA. OverflowA has to drain X gallons back into the sump where PumpA pumps it back into TankA to keep the circle going.

Just make sure that both return pumps are in the same compartment and that you keep up with your top offs so that the pumps don't run dry.

 

Ok makes sense so far. What happens if the overflow flows too fast. If it runs out of water because the pump isnt keeping up will is loose syphon? Or will it be able to start flowing water to the sump again after the pump gets more water to it?

 

If the flow is too slow then you definitely will lose siphon. That is something I have never faced as I always tend to end up with more flow than the tank can handle instead of less. If you use 1" overflows, that puts you in a 600gph range and getting it dialed in is something you just have to work on to get it where it won't lose siphon. My apologies for not mentioning that as I have never had that issue so I very seldom think about it unless its mentioned

 

So how do you get it dialed in? Is there an adjustment on most pumps to change flow or is there some kind of valve you have to use?

 

How do you start the siphon of your overflow? Mines set up so that in the case of a powercut it won't loose siphon.

Phil

 

If you have a good overflow system you shouldnt loose syphon. If you are worried you can go with redundant overflow tubes or use an aqualifter pump to pump out the air that tends to collect over time at the top of the tube.

 

Havnt got one yet. The more I hear about this the more having my tank drilled sounds better. All it has is water and a couple of rocks in it anyway.

 

Drilled is definitely preferable to using an overflow. Just make sure that glass isnt tempered because you cant drill that.

 

Mike, yes, a ball valve on the pump and you adjust the water flow. If the tank only has water and rocks in it, I would remove them and drill it. It makes it a lot easier since you don't have to worry about siphons.If you an external overflow, you don't even lose tank floor space.