I finally found some de powder and put 2 8oz cups of it in my skimmer. It immediately blew out thru the jet. Husband installed a valve between the pump and the sand filter but we not sure how to use it. Do we just set it to lessen the water flow by half, therefore not pushing the water thru the sand so fast? We have a 200lb sand filter with a 1.5hp pump. Do you think this is why it does not appear to be properly filtering?