FC Usage?

Ravenfan1969 · May 13, 2015

Hello all! I am in need of some input on my FC usage. Last season I was losing approximately 3 to 4 ppm of FC per day. I was holding a 60ppm CYA last year. This year my numbers after SLAM are,

5ppm FC
0 CC
7.6 PH
130 TA
40 CYA

My pool is in full sun all day. Yesterday it was cloudy and only lost 2.5ppm. Today and Monday lost 4 to 4.5 ppm. Should I raise CYA or is this about normal? I am located in Virginia in case thats not in my sig. Thanks in advance.

Ravenfan1969 · May 13, 2015

Also I performed a OCLT and lost no FC last night. Pool is clear. Temps have been between 85 to 90 past few days. Pool temp is 78 to 79 by day.

Azgirl71 · May 13, 2015

Welcome back. Sorry it was under these circumstances. You are correct. Your PH will be incorrect with FC levels over 10. What was your PH before you started to SLAM?

Your CYA is at a good level for a SLAM. What FC shock level are you targeting?

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Also, what does your water look like?

pwrstrk · May 13, 2015

Are you confident of your CYA level of 40 ? This time of the year and your water temp not that high you shouldn't be losing that much now. You passed the OCLT correct ?

YippeeSkippy · May 13, 2015

Yes, sometimes pools in full sun do require a bit higher CYA level. I'd suggest performing an OCLT test first overnight to determine if there is any cooties growning. If not try raising your CYA to 50 at the most,and monitor. Remember that CYA doesn't leave without water replacement so you never want to risk over doing that if at all possible. Make sure your test your CYA with the sun facing your back, the tube held down by your waist.

pwrstrk · May 13, 2015

Just wanted to add and I forgot, I keep my CYA at 40. My pool is in full sun also and at the most I lose 3.5 FC a day. That's with water temps in the high 80's to 90.
Are you seeing a fair amount of pollen ?

Ravenfan1969 · May 14, 2015

Yes I performed the OCLT test. There was no loss overnight. There is still a fair amount of pollen as I can see it laying on water surface. I was thinking that may be the cause. I was just concerned that with my CYA last year at 60 I was losing a bit less and I do not want to raise until I am convinced that is necessary. I have trouble reading that test and will retry later today to confirm. I did drain the pool down just below skimmer and it was dropped about an additional 6 inches or so from pumping the water from the cover. I thought that was the culprit for the CYA drop. Pool looks great! It was crystal clear from the moment I uncovered. Ran the vacuum and brushed and Saturday after top off it was beautiful,.

pwrstrk · May 14, 2015

The pollen will also consume some FC.