Greg:
< than 5 minutes twice a week and everything is squeaky clean....
At an average cost of $520,000 for lots averaging < 6,000sf...there ain't much room for ponds, much less humoungous filter bays... Plus I have better things to do with the 1/2 hr to clean them...bet it's more like 1 hr... use to have one, 3' x 4' x 20' 4 chamber up and down flow...That's why I quit in the 70's....Surf was always up, so pond was always dirty...
Aloha! Mike