No Chlorine Murky Algae

[jodijo]

Hello,

Newbie here and to pool "ownership" ... Please forgive my near idiocy regarding terms, etc.

After initial maintenance to open (20,000 gal., chlorine, inground, about 15 years old) pool, my efforts to keep it clean (basically just running Aquabot Turbo for two hours every day, adding 1 1/2 gals. liquid household bleach weekly, shocking with DuraShock twice) the pool was crystal clear and water felt great for a couple of weeks. Since then, pool has been a disaster for two weeks. Testing at home shows no chlorine, low CYA, low pH. Algae growth began then. Testing at pool store revealed phosphate level (lawn gets treated), so we used rx of shock, PhosFree, algaecide (second treatment then) and back-washing. While follow-up testing reveals no phosphates or other reason, algae growth has gone rampant despite shockings and lots and lots of sweeping to the drain with brush. Ran Aquabot every day until three ago, but I continued lots of sweeping of algae to drain. Have back-washed several times. Last night, I did pool store's rx -- Added 10 gals. chlorine (purchased at pool store), 32 oz. algaecide, and left pool running. This morning found 0 chlorine level and murky algae looks same. Vacuumed but am only getting sand in new Pool Blaster Max filter.

Not sure if this is significant, but there is an automatic chlorinator tablet dispenser (word ?) at pump.

Any help would be greatly appreciated.

Thanks a million for any time you can spare.

Jo

P.S. - Follow up: Went to different local pool store minutes ago ... Was prescribed banish algae treatment and 3 one-pound bags shock, keep two chlorinator tabs in skimmer to help chlorine level, then vacuum. Automatic chlorinator may be clogged. Seeing a lot of sand also ... Wondering if only two-years-old sand may now have a bad pipe?

Hope this works!

Also, I misstated pH -- It is high, not low.

Thanks again for any advice offered!