Combined Chlorine

[tcat]

Does a CC reading of "2" always mean you need to shock? I've had low CYA and adding Trichlor tabs to increase it. My FC is around 6 (only needs to be 2 or 3 at CYA 20). Could the high CC reading just be that my FC is high, or should I just shock (since shock level is so low at this CYA)? Water looks clear.

 

[JasonLion]

Yes, in your case you need to SLAM the pool. If CC is high and FC is near zero, sometimes simply raising FC to normal levels will get rid of the CC. But when FC is already at normal levels, you need to SLAM.

 

[tcat]

Slamming. Before slam, fc was 4, cc was 2. One hour after slam, fc was 12, cc was 0. But yeah, overnight 12 to 10. Be checking it every hour or two today.

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[tcat]

OK, passed OCLT last night. CYA was 20 (or less), so slammed to 10-12. Lost .5 last night (11 to 10.5) with zero CC (very very faint pink, so maybe .1). Today after 1" of rain and 3 or 4 hours of sun FC is down to 9 and CC is at 1. Pool is clear (and was before). I also have had Pucks going with auto feed set at 5 to raise CYA (and FC) since 7 AM, yet FC has still dropped to 9. I know that's still high, will CC go down once FC has settled at 3 or 4? I'm thinking at CYA 10-20, FC can drop pretty fast so Pucks probably aren't keeping up. Will start maintaining with Clorox at FC 4 (or after CYA = 40 if Pucks keep up at the lower levels).

Edit: Did "reverse" oclt last night to see how much fc the pucks were adding. Went from 6.5 to 8.5 in 12 hours. So I can translate that to 4 power day from 10 pucks. Hopefully adding about 2 day per day. May buy some stabilizer to speed things up.