I just can't imagine having a large clear, clean, and healthy pond without
a BD and with gravel on the bottom. In our pond we have
a shallow beach section, that we have rock in that section on the bottom. Years
ago we had small pebbles and had to change it to
bigger rocks because of all the crap
getting stuck in the pepples.
Every couple of weeks we hose the beach section to losen
out the fish waste and it gravitates toward the bottom
drain. Also the amount of waste that we take out of the
first tub each week
You have to consider that the BD function is to
filter the water and remove the waste continually,
thus there is no need to empty it every two to four
years for cleaning.