In a word...yes. You probably are okay with the filter you have, but a 1.5 HP pump is way too big for your pool. However, with it running in low speed, it may not be bad--Pooldoc, Mark, or one of the other equipment gurus should be able to better advise you there. I just know that my pool is roughly 25K gallons, I have a 300 pound sand filter and a 1 HP pump and it's plenty big enough.

Janet