matching sump level

Ive just set up my sump behind my main tank.The water goes into the sump via gravity and returns to the main tank via an adjustable pump.The problem im having is matching up the inward and outward flow.Is there any easy way to do this as I cant get the balance right either to much into sump or too much out of sump.Im using 16mm internal diameter tubing and the pump is 1000l per hour adjustable.
Would smaller or larger diameter tubing work better or someway to limit whats coming im?
thanks

 

If I am not mistaken, you control your flow with the pump that is in the sump. If you want to process 600gph then you would get a pump rated for a bit higher to adjust for gravity. The amount of flow should not be much more than what your skimmer can handle.

I have read people using a 1" line to supply the sump and a 3/4" line for return, with a ball valve on the return side, which will keep the DT from overflowing if the valve gets plugged.

I am looking more into this as I am also new.

 

Your overflow should have little to no resistance when draining to your sump.

I found this table that may be able to help you plan on the size of drain pipe.


The typical amount of water you want to go through your sump is about 10x the volume of your DT. I hope this helps..

 

I'd like to see some pics of your setup.

With the sump under the DT, your drain would be unrestricted and the overflow would maintain the water level in the DT irrespective of the actual flow rate. IOW, adjust the pump to the flow you want and the water levels would balance themselves. I can't quite imagine how you have the sump behind the DT or how it's plumbed that would allow too much water to drain out and cause the issues you're having with it.

 

This sounds wrong. There shouldn't be any problems because the drain can only go at the speed that the pump is running. I for example have 2 pumps in the sump and everything works fine if I were to turn one off.

Where did you drill and do you have an overflow wall/box? I'm guessing you drilled low and don't and are trying to pump the water back in the tank at the rate the whole thing drains in which case you need to completely start over. One power failure and goodbye tank (or even just pump slowdown with age).

 

Photos?
The return pump will determine the flow and the overflow will balance itself out if it is designed correctly with no restrictions and the proper water/air mixture.

 

Just because it hasn't been mentioned, how are you getting the water to your sump? It seems like you might not be using an actual overflow to get the water out of your DT to the sump. It sounds to me like you may just be using a siphon tube that runs directly from the DT to the sump since you say you need to match the inflow from the sump.