I've had a DE filter for 13 years and have just grown tired of the continued maintenance and it appears to be on it's last legs. After reading thru some of the topics it looks like I will switch to a sand filter and add DE. Success with Zeobrite seems to be determined by the quality of the Zeobrite you purchase. So my question is - 15k gallon pool - what would be the recommended sand filter size and pump HP? I was thinking 3/4 HP pump and a 36cf filter. Any feedback would be appreciated. Thanks.