We recently opened our above ground salt water pool. It is 27' diameter with 52" walls. Approx. 17,300 gals. We had a green pool on opening so after adjusting pH, shocking and adding salt(we had to add quite a bit of water to get to skimmer-level) we added algaecide. We live 50 miles from the pool supply store, so we resorted to Wal-Mart brand. My husband dumped in an almost full 48 oz bottle. Now, we have FOAM!! And no matter what we do, our free chlorine levels do not register. Also my copper ion level is high. Is there any way to fix this other than draining and re-filling?