New pump and filter pressure

We installed a new pump this year. I was advised to change from a 2hp pump to a 1.5hp. We have a 24ft AGP, with a 250 pound sand filter. I have had issues with my pump losing suction with anywhere from a .5 to 2 psi increase in pressure. I first noticed it when vacuuming and I was told there was an air leak. The pump filter basket has only a small air bubble that doesn't change size. I replaced the vacuum hose and the skimmer adapter - it still happens. I backwash it until clear and then for another 30 seconds to a minute - wasting a lot of water. When I turn it back on to filter it is 17psi. After vacuuming for anywhere from 30 seconds to 3 minutes, it loses suction and the psi may have gone up .5 to 2 psi. I then backwash and it doesn't even appear dirty. Everything I read says that you don't need to backwash until there is a 6-10 psi increase in filter pressure. Why would mine be .5-2psi increase? I replaced the pressure gauge yesterday. Is the 1.5hp pump undersized fro the 250 pound sand filter? I have been effectively fighting an algae bloom, but have the pool nearly clear.

Thanks for any advice.

Have you checked for an obstruction in the vacuum line?

I can tell you that the 1.5 hp pump is not undersized for your filter--I have a 1 hp pump and 300# filter on my 29K gallon pool, and it works great...

Janet

Yeah, something seems to be set up wrong.

Carl

I wish I could figure out what is set up wrong. The vacuum hose is new and it did the same thing with the old hose. All gate and ball valves are fully open. The pump strainer basket is clear of any debris.

What pump model did you have and what do you have now?

Current:

The pump/motor have the following info:

EcoKleer

Waterway pump 1.5hp
Model #SD 1007137411
Motor 1081/1795 pump duty
Century Pool Part 0-177894-24


Old:
There is only 1 label on it but imprinted on it is Waterway Hi Flo
Century Pool/Jetted Tub Motor 2hp
1081/1795 pump duty
part number 7-177894-24