I would do just what Jason mentioned as the rocks and sand have absorbed the PO4's I had a similar issue with Rocks reused from a well water system.. Took me 6 months of ROWAPOS and a reactor to get them out I used 5 tbs spoons at a time and changed it out bi-weekly .. As for a water filtration system look into the new units Kold sterile No waste water and a great system it will not strip the water of natural Ca and Carbonates .. Just want you don't need or want.. about 20,000 Gal of product water between recharging We use them on well water for our coral growing systems and all who have gotten corals from us seemed to be very happy with their health . I like the no waste water myself. and they deliver 3 GPM .. _________ Some of the world's greatest feats were accomplished by people not smart enough to know they were impossible (Doug Larson) |