Trouble keeping FC high enough


Gold Supporter
Sep 8, 2018
Barrie, ON, Canada
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
Hello all.

I have an approx. 10,000 Gallon vinyl pool. Pool builder supplied / installed an IC-20.

CYA of 80.

I've been running the IC20 at 100% from 8 AM until 8 PM. Per PoolMath this should produce approximately 4 ppm FC. Most daily testing only showed around 3 ppm mid-day ish in the pool.

I've increased pump run time from 7 AM until 9 PM, which in theory should raise FC by 5 ppm.

CYA is 80, so per FC/CYA Chart I should be targetting 6 ppm FC. Daily testing is still only showing approx 4 ppm.

I've been supplementing with liquid chlorine, but I'm wondering if there's anything I'm missing?

How much can I expect daily sun to effect the FC level?

OCLT is a pass with 0 loss overnight.

CYA 80
FC 3-4
CC 0 - 0.5
PH 7.5-7.8
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