You do not need to worry about that with 3-4 water exchanges per day.
I asked abot the drain because with that much water flow, you could use the water flow to help remove some of the mud and sludge from the bottom of the pond. You would need to put a tee fitting (not an el fitting because it could start a siphon) on the drain pipe at the water level and run a large piece of hose down to the bottom. If it is flexable hose, you can move it around every day or so to pull mud from a different area of the pond. Probably would not work if the pipe is more than about 15 cm. Something like this....
-steve