We have had an above ground pool on our backyard for the kids for a few years now. I always drain the pool after the summer and refill it around May. I could always get through the season by using the 3'' chlorine tablets + algae guard + liquid chlorine. This year I did as usual but about 1.5 weeks ago my pool just suddenly turned green and if I don't touch it I have dead (I assume) algae settling to the bottom but if I brush it a bit it turns the water green and you can see only about a foot down and all murky after. I upgraded the original cartridge filter to an Intex sand filter and has been running for 3 days now continuously but does not seem to make any difference. I checked the water using my kit (HTH strips) and all within the ideal range other than the FC is 10+ and the CYA is ~100. I am very frustrated and about to cut that piece of junk into pieces and throw it out to the trash but may give it another shot:
1. Should I just drain the whole thing and start it over and use that 3'' tablets very carefully, checking the CYA every 2 days to make sure I don't pass 60-70 (South Texas, water temp is 90+)? It costs about $50 to completely refill the pool but it takes about 3 days .
2. Should I try a partial drain (maybe 30%) use some some kind of algaecide to try to kill of the algae? The algae already appears to be dead, it does not stick to anything just settles to the bottom. Will the sand filter filter it out eventually?
They should really put a warning label on those 3'' chlorine tables to stop using after a while. The instructions are very misleading, "treats up to 10k gallons for a week" and "shock'n'swim", shock it once a week and all gonna be fine. I spent several hours of researching all over the web and now I have a better understanding of why my pool got all messed up.
Any suggestion is welcome, at the moment I have no better idea other than completely drain the pool over the weekend start it over .