We've been preoccupied with a pet emergency for the last couple weeks and the pool has been a little neglected. (One of our parrots broke his leg.) The pool went ten days without removal of the bubble cover and testing. Normally, I am pretty religious about maintaining the pool and keep the FC at or above the BBB recommended level relative to CYA (currently 4-6 PPM). Historically the chemistry in our pool remains exceptionally stable. Normally I test once or twice a week and this pool historically has a very low chlorine demand. [When we bought this house and I began maintaining the pool the CYA was over 120 and it has taken a rainy winter and a few short drain and fills to over more than a year to get it down to about 50. Next winter I will have it where I want it (Water here is very expensive.)]
Yesterday afternoon I tested and found the FC to be 1.0 ppm and PH @ 7.5. All I had time to do was add chlorine and test. Yesterday evening I did a basic test again and FC was at 6.2 and PH 8.0.
This morning I did a full battery of tests and removed the cover. The numbers are as follows:
Temp 82 f.
So there was no chlorine loss overnight; there is no CC and the water looks clean and clear. Problem is that there is a big patch of Mustard / Yellow ? Algae on the North facing side and some small areas on the north facing risers of the the top two shallow end steps. From what I've read you guys say shocking is mandatory if there are signs of algae.
It seems kind of a shame to dump all that Chlorine in there, but I have come to trust you guys implicitly.
Anticipating a big bump in PH with the added ChIorine in the last hour I adjusted the PH down to 7.2 and my plan is to raise the FC to 20.
So, what is the minimum time I have to hold the pool at shock level?
I have done a good brush down and will repeat.
How aggressive should I be in cleaning? light housing? skimmer parts, drain?
Should I add something to my sand filter like "Fiber Clear" to increase its effectiveness?
I expect it will take quite some time for the FC to come down from shock level, because as I remarked above the FC seems to be holding at its current level and this pool has a historically low chlorine demand. I know this question gets answered frequently but is it really okay to swim at this high chlorine level?
I know you guys aren't crazy about polyquat but I am contemplating on using some as more of a "belt and suspenders approach. Are there any drawbacks to using this chemical other than cost? (Yes, I know "it's no substitute for proper chlorine sanitization.
THANKS IN ADVANCE FOR YOUR ANSWERS AND COMMENTS.