Water level difference -- Normal?

dopey · Mar 4, 2018

I have an aqua medic yasha.. I couldn't source the original return pump, so I DIY with a SW-4 + pvc.

Flow wise these are comparable pumps.. Yet I am seeing a large delta between the back sump water level and the display tank side.

This is with the pump on lowest setting, increasing flow results in a bigger delta..(*surprise*)

The main problem with this is a very sensitive range between 'full to the rim' and 'sw-4 is sucking air' ..

The back area has two glass pieces in the tank. The first one the skimmer hangs on, and the second is a bit higher from the water leaving a 2-3cm gap between the two. believe the intent is to let water flow 'under' the two panes of glass and be sucked up by the pump.

I do have a bag of carbon in the bottom, but even without that carbon I still had a large delta between display tank and 'rear sump' area.

Common? or suggestions how to mitigate it? I've thought about plumbing an actual return pump that sits on the bottom instead of this SW-4?

cgdcinc · Mar 4, 2018

Having a return pump and moving the sw-4 to the main part of the display tank. Try them out of the sump.

five.five-six · Mar 4, 2018

Pump flow rates are really gueatimates. The amount of head or back pressure has different impact on different pumps. seems you have more flow, which is good

dopey · Mar 4, 2018

The flow itself isn't my concern, its the fact the pump area runs at such a lower level than the display tank. Makes positioning the ATO tricky, as a 'safe' level for the pump is quite full on the front end of the tank.

Luno · Mar 4, 2018

If your worried it is too low add more water, obviously you are moving more water than the previous return was. If this is not working with your current setup as you say there isn't much room between full to brim and the pump sucking In air you only have two options.
1- change the return pump to a pump that sits lower.
2- enlarge the return section so the volume is greater and will require more water to create a difference in volume.

Your ingenuity is a good try to create something to work but as you describe it is not working out for how you would want your system to run.