I have a 27,000 vinyl liner. DE filter with 1.5 hp Hayward Super pump. Opened green pool with 5 lbs granular Bio Guard Super Soluble. Cleared pool up pretty well. 2 days later, took pool sample over to store and was told to ad a variety of products for ph and stabilization- also 6 bags of shock. Pool looks great, but test strips are showing 0 FC. Another test at pool store- still 0 FC. They told me to add 9 bags of shock. Test strip is still showing no chlorine, however, a test with my kit with the drops shows adequate chlorine. What is up?