So i've been battling back and forth with this for weeks now.
Current water chemistry
FAC & TAC - .5ppm
CYA - 30ppm
Alk - 40
pH - 7.4
phosphates - 0
Heres my quick timeline from buying the house until now. Throughout all of this my chemistry has been pretty good with the exception of chlorine. When i start having algae issues, chlorine drops. After i had the first issue, i had a problem with FAC not matching TAC. Shocked it with Leslies Fresh N Clear which solved that problem and the chlorine stabilized as the algae died off.
Pool is a 16x36 inground vinyl (24,000gal) with hayward multiport sand filter, offline auto chlorinator. No main drain, 2 skimmers on one side of pool, 2 returns on other side with 2 smaller return jets in pool steps. Clean filter pressure around 12-14psi. Dirty somewhere around 18-20psi. Also have a Black and Yellow maytronics dolphin. Bag always washing machine washed after every use. He doesnt seem to climb the walls anymore, but i always brush walls before i drop him in.
June 27th - Closed on new house, water reasonably blue, but cloudy
June 28th - Shocked pool with 4bags CalHypo, set auto chlorinator to high. Couldnt get cap off, but previous owners told me they had just filled it. figured i'd deal with it when i got home
June 29th - left for a week vacation down south
July 7th - come back to a swamp of a pool. Finally got the cap off of the chlorinator only to find the bottom completely caked solid with chlorine about 3" deep. Removed chlorinator and replaced with brand new. Filled with tablets, set it to high.
Between July 7th and July 14th - Shock pool daily with CalHypo, vaccum, backwash, etc until pool finally clears up to cloudy blue. TAC/FAC not matching for a few days, shocked with non chlorine shock and it freed everything up. Pool got clearer, daily chlorine levels stabilized
July 15th to July 23rd - Pool blue, but always semi cloudy. Clears up better some days than others. Shock once every 3-4 days with Sodium Hypo (cheaper) bag shock. Auto Chlorinator still on high. Chlorine levels holding around 2-3
July 22nd-23rd - Very windy days, pool filling with leaves and debris quicker than my skimmer and filter can get it out. Everything in pool overnight settles to bottom by morning
July 24th - Pool starts to turn slightly greenish. Chlorine levels dropping to .5 to 1. Threw a floater in the pool set to 40,000 gallons with 3" tablets as well at this point to try to keep some FAC in the pool. shocked with 2 bags SodHypo
July 25th - pool a little bluer, Shock with 4 bags sodium hypo
July 26th - Pool light blue again but still cloudy. Crevices and walls consistently have brownish algae, that requires brushing but never really goes away
July 26th to 28th - Walls and crevices still have brownish cloudy algae. Continuing to daily brush, vaccum with Dolphin, and shocking every 1 to 2 days.
July 29th - Throw in 3bags of SodHypo shock, and half a bottle of "Sink n Sweep" floc.
July 30th - Pool crystal clear, first time i can see straight down to the bottom, but entire bottom and crevices covered in brown residue. Throw dolphin in this morning to hopefully clean up everything on the bottom but come home at lunch to semi cloudyness and half of an uncleaned shallow end.
So my thoughts are that i still have some residual algae eating up my chlorine, but the floc is sinking everything. So i should shock the heck out of it tonight with 4-5lbs of SodHypo, use the other half of the floc to settle everything overnight, and then vacuum everything on the bottom tomorrow morning to waste and not bother with the dolphin until i regain control of the pool. Shock it again on weds night and repeat until water is crystal
Thoughts? pics attached. One pic is normal cloudyness, the other two pics are this mroning with everything sunk to the bottom.