Hi. I replaced my ec 30 hayward filter with an ec 40. I have also replaced the motor seal , motor and impeller. My issue is that even with a clean backwashed filter my filter pressure jumps right to 17 psi within minutes over 20psi then within a half hour over 25 and stops discharging water. The filter is new and clean, there are no airleaks and pumps great at 17 psi. my motor is 1 hp 3450. Is my impeller too big? scratching my head. Thanks