| Is the space available to this pond builder a constraint? Because I think he needs an 8 foot diameter settling tank and 1/4 horse power pump for each bottom drain, and a 1/4 horse power pump can pull 5000 gph if you use a 2.5 inch suction line and pond return pipe after the biofilter, mine can anyway.
When I built my sixth pond and made mistakes with each, by then I was friends with those kings of practicality and droppings, the Sewage Treatment Guys. "Its all about dwell time", they told me as a visited their installation with a kerchief around my face like a bandit, "You need a 15 minute dwell time in a wide diameter tank to give the settlable solids time to settle out".
Now, I had peered into those 4 foot diameter purpose made vortex tanks that were around at the time, each costing as much as a pedigreed cow, and saw the particles whizzing around at dizzying speed. No wonder we now had to, the dealers told us, buy yet another terribly expensive "peice of kit" to remove the, why, 40 to 80 percent of the particles that went whizzing through the vortex tanks, boundry layer or no!
So I figured my pump could put out, with the special 2.5 " piping, 5000 gph.The 1500 gallon 8' diameter settling tank I made out of a poly tank from a farm store costing $400 and filled up to 1250 gallon level, gives a 15 minute dwell time. The 4 inch drain pipe from the pond enters the tank 1/3 the way up and makes an L turn. The two 4" pipes to the biofilters are near the top of the water level and draw from the side, (sorry JR).
Perhaps the pond builder could have one 4" pipe off a properly sized settling tank go to a submerged biofilter and another going to a tank from which the bakki shower drew.
While I have lain awake nights thinking the same things about forces affecting the particles of droppings as you gentlemen, I have always fallen asleep before reaching any conclussions. However, I do know that this arrangement works. SMG |