It’s a perfect bottom and surface drain, but how do you prevent fish food loss from the whirlpool? Any thoughts?
The velocity (speed over distance) of water may be too high simply based upon the whirlpool effect it is creating in the tank. Could this be slowed down a little? Depending on the fish you are raising a high velocity can be stressful and may just be impractical. I agree your solids removal is probably excellent but you may need to just find a middle ground. Reducing the velocity may be all you need to allow fish feed to stay buoyant long enough for them to eat. A few questions are: Are they eating? What fish do you have? What is the flow rate of water in and out of the tank?
This tank is for American Shad. Velocity looks high, but it’s within the recommended rate (30cm/sec), and the fish love to stay at the edge of the fish tank, where velocity is the highest. This species seems to love high velocity.