While setting up my DT initially, I designed the return pipe from the sump with minimal bends in order to allow the pump to be efficient. there is a total of 3 bends.
I placed a ball valve on the return pipe, which proved invaluable. If the ball valve is fully open I get a lot of micro bubbles at the end of my return pipe going into the DT, when I adjust the valve, the bubbles decrease but my return pump starts getting noisy.
There seems to be a magic spot that regulates the flow enough to minimize the micro bubbles coupled with the sound my pump makes. I also have to adjust the flow of the feed pipe coming down from the HOB
overflow to balance things out.
I'm attaching a few pics of the return pipe configuration in hopes someone may have an idea on how to minimize these micro bubbles.
For reference, my return pump is Aqua Medic submersible pump rated at 3500 liters/hour (925gph). Could my pump be too large? My DT is 450 liters(116gallons), sump is about 20 gallons.