I purchased an above ground pool in July - it was great until 2 weeks ago when algae suddenly took over the pool. I've read how to slam the pool and I'm ready to try that. However I don't think the pump that came with the pool is an adequate size. It is a Intex Model 637R. On the Intex website, I don't see any info regarding how much water this actually circulates or what the next best option would be. The local pool store wants to sell me one for $300 (which I think is alittle excessive). I have no idea what I'm doing - just learning. Any suggestions?