22ppm FC and 1ppm CC

May 24, 2010
200
Dallas, TX
With swimming season here decided to get some good numbers and behavior on the pool we've had since we moved into our current home last year. Never got the hang of testing for CYA with my TF100, so my local pool store told me had a 35 last year. Basically what I wanted and where I was at with the previous pool (and brought my 3/8-adapted Liquidator with me). Problem was, for the last few months, the pool has been EATING chlorine and could never keep levels up, for the size of pool I was guessing we had (32k gallons). Checked CYA again myself, was at least less than 20 and nowhere close (didn't have enough pool water/reagent mix, but the black circle was still perfectly clear). Pool store told me I had 0. Great. Apparently I've had more splashout that I thought? Calcium hardness was 175- and I've been using a lot of calcium hypo recently as I've been working through WS Liquidator problems (clogged up the float valve holes). And my FC was definitely 0.

So I dumped in enough CYA to get 32k gallons to a 32 level yesterday afternoon, and through in 8lbs of 65% calhypo last night and let it run all night. This morning, had a 22FC and a 1CC. Does this mean it's just still working it's way through all the organics/whatever else? I very typically have a 0CC so guessing this is from all the shock? I've put in that much many a time before, but never measured FC/CC within a day. Then I'll go back to using the Liquidator :)

On a side note, using the pool calculator, 8lbs of 65% gives 22FC on a 28k gallon. Assuming I've had no FC dissipation (which I know there had to have been some), I can set the upper limit of pool size to 28k gallon (if FC was higher last night after dumping in, which it had to have been to have made 1CC, then the pool is even smaller).
 
Well, 1 ppm CC still indicates the need to shock so you should continue doing that. You should be careful when using cal-hypo though as it can really drive your CH up. A very high CH can cause problems with scaling.
 
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