We are in our secong year of pool ownership, but earlier this year we converted successfully from Baqua and have never looked back. But now we are having some concerns as regards the balance of CYA and chlorine in our full sun situation. Pool has been trouble free since the conversion.
On 7/14 a simple evening top up of our water turned into an accidental overnight flood (left the hose on) followed by a backwash to bring the water level back down, and a subsequent examination of current chemical status. My DH had been keeping the CYA at what he thought was 30, and the rate of chlorine use indicated that we needed to increase that to compensate for full sun. We had added CYA a little over a week before to increase it to what we thought would be 50. The pool really does get full sun all day every day, and we have a clear bubble solar cover (new, installed after the baqua conversion). After the flood, the water looked greenish the next day, but no CC present. We are on well water, but no super high levels of metals or anything.
After the unplanned dilution situation, our levels on 7/15 morning were:
FC 2.5 ppm
CC <0.5 ppm
TA 210 ppm
CYA 40 ppm
We added the requisite chlorine to hit 6 ppm. I added a CYA sock to get just above 50 ppm. I added muriatic acid to lower pH to 7.2, and had kids splash to start the aeration necessary to start lowering the high TA. I did not check CYA or pH until today.
When I tested today (7/17), the CYA seems to be about 40-43 ppm (I massaged the sock so it got into the water within 24 hours), and our FC still drops to zero every night... We are using so much chlorine, it feels crazy. I plan to do an OCLT tonight and check for CC. Today, we also noted a lot of yellowy sediment on the bottom of the pool that vacuumed easier than dirt (live algae? dead algae? nothing of concern?). The water is truly crystal clear today, no longer green. pH is 7.2. Do I need to keep waiting to see if the CYA will go up, even though the sock has been emptied, or is this what it really is?
I read in a different thread somewhere that if it were bad CYA or not what the canister claimed (what we have used up to this point comprised 4 4-lb canisters of HTH brand purchased from Meijer) it would obviously not bring the level up as expected. I have a new 6-lb canister of a different brand bought at an actual pool store and will use that to get it up to 50 ppm (after I hear back from you all whether or not I should wait longer for the last batch). From now on we will add Cl at night, but still it is getting down to unacceptable levels by the end of the day.
Thoughts? We're confused. We appeal to your expertise!