I found old threads talking about this issue but no solution. Has anyone recently experienced a decrease in flow with these pumps or have a final fix to solve the problem ? I get my tank level set every two weeks with WCs (return pump gets turned off/on) and then over the course of the next week or so the water level in the display tank slowly goes down. I’m not sure why the pump slowly decreases output but it’s driving me nuts. Thoughts?

