I used to get pressures in the high 20's before I would clean the filter and replace the DE. I have a 1H.P. pump connected to a Haward EC-50. No visable signs of air in the pump strainer or at the pool jet. (above ground pool) Does anyone know what the max output pressure should be from a Power flo sp1580 1 hp pump? Not gpm or other type of flow ratings but what is the max pressure that this pump should put out if it is completely obstructed at the discharge. Thank you.