We have joined the ranks of those leaving Baquacil behind... followed pool stores instructions using potassium monopersulfate shock, trichlor tabs in the chlorinator, and made it out of the cloudy green stage and up to clear aqua water. Changed sand. Then they switched us to regular dichlor shock, but the pool turned green again - not cloudy, but clear grass green. Happy St Patrick's Day green. Also more yellow/brown tufts on the bottom of pool, which we suspected to be more biquanides still in the water. After two weeks of green water, shocking every evening trying to get shock to hold, I lost faith in the pool store... especially because they printed out a set of instructions from their computer analysis, but told us to do differently... Example: the total chlorine was 10, free chlorine was 6, and the computer analysis said our free chlorine was too high and to use the Oxysheen (potassium monopersulfate) to eliminate combined chlorine. But the employee marked that out and told us to put 5 lbs of super sol shock in the pool. Whaaaat? I started ignoring their personal instructions and followed the printed sheet and the water began turning lighter, aqua, and is now blue again. QUESTION: can we continue to use potassium monopersulfate to shock once per week for the rest of this season, in combination with the trichlor tabs in the chlorinator, and then go to dichlor shock next season? This was one of the recommendations I found online and it seems to be working much better for us.