Normal FC loss?

[jasnovanorder]

What is a normal average amount of daily FC loss? Last night I raised my FC up to 10ppm. After vacuuming. Checked it a little while ago and it's down. So I checked for CC and a double check of the CYA Tonites tests results were
FC 7
CC 0
CYA 50

the pool sees most of the mid day sun I would guess about 5-6 hours worth. Is a 3ppm loss with a 50 CYA about average

 

[Texas Splash]

Depending on your location, CYA, etc, normal FC loss is around 2-3. If you ever have additional doubt, you can raise your FC to SLAM level and perform an Pool School - Perform the Overnight FC Loss Test (OCLT). But I think for now you're good. If you have any more questions or concerns, you can always post a full set of test results for us to review. Have a nice evening.

 

[Richard320]

2 to 3 FC per day is pretty normal.

You lose a percentage to sunlight, not a fixed PPM. So at higher FC levels, you lose more. That's why you can't just dose the pool three days in advance. It's not a fixed amount. The recommended levels take that into account. Overchlorinating just leads to higher UV losses. If you lose 3 per day, and minimum is 4, target 7 or 7.5, not 10.

 

[DanielP]

When you say you raised FC to 10ppm last night, is that based on Pool Math or did you test 30min-1hr after adding chlorine?

2-4 ppm FC loss is normal, the more sun, the higher the loss. The higher above the target FC level, the faster it is lost because you have extra chlorine that is not bound to CYA. Your CYA is 50, the target is 6ppm FC in the Chlorine/CYA chart. I would drop your target FC from 10 to 7 and see how much you lose by tomorrow. Do today's test after your chlorine addition has mixed for 30 minutes at least, possibly even stir with a leaf net since the OEM Intex pool circulation isn't very good.