Pond Boss Forums INTRO Questions & Observations After 2 yrs of setbacks

Bob-O>The HP 120 is a very good pump in the right situation.It will operate on 60 hz for you vs 50 hz which is better. The startup pressue can go to 7.5 psi back pressure but must operate at no more than 4.5 psi (which will give you 2.5 cfm) which if you keep the airstone clean you will be fine. As far as putting it in 12 ft of water this will create at least 6 psi back pressure which this pump will not operate for long at and would drop your cfm to "1"With a 4.5 continuous psi rating you would want to be in no more than 9 ft of water.The open flow of that pump "zero back pressure" is 6.1 but linear pumps drop off cfm quickly as your water gets deeper.Try to feed your airstone with at least a 3/8 inch ID line,As far as calculating turnover it also depends on what type of stone it is, If it is a medium pore and you stay in the 4 psi range and dont overload the pond for a high BOD you should be fine.Monitor your back pressure with a stone diffuser and be able to remove it and clean it as the pressure goes up. Good luck