Is it normal to lose this much FC in one day?

[durtynacho]

My CYA is 60, so I try to maintain a FC level of 7. PH is 7.6 and TA is 120, CC is 0, and lastly, it is an outdoor 22,500 gallon pool in the north Texas heat. But, my water is clear.

Anyway, I will add chlorine at night to get my levels up to 7 and by the following evening they may be as low as 2.5 to 3. In the morning they will be around 6, but by the end of the day they are much lower. My CYA used to be 30 but I upped it to keep the sun from burning it off as fast, but it seems to have not made any difference. Is a drop in FC by 4 points a day normal for 95 degree Texas summer heat, or do I have something else consuming the FC (algae) that just hasn't altered the clarity of the water yet?

 

[YippeeSkippy]

4ppm loss is on the high end of possible, but one way to determine if there is something in the water chewing it up is to perform an OCLT (overnight chlorine loss test) and see how it comes out- Overnight Chlorine Loss Test

If nothing shows up on the OCLT, I'd raise my daily goal to 8 or 9 and see if that helps you not bottom out so far down. Your bottom line acceptable FC is 5ppm, lower than that and you're at high risk for algae.

Yip

 

[durtynacho]

Yeah I've done that with no more than 1-1.5ppm loss. It must just be too hot here.

 

[Scoop]

durtynacho

I'm in Dallas County, just north of you with a 15k gunite outdoor pool (no SWG) . Here's my typical #'s :

CYA 50 I usually maintain it between 40-50 .
FC Range 4-8.5 I like to target the max dosage about 0.5 higher than my FC/CYA range max.
FC daily loss: It varies with the season but generally in the summer, it depletes between 2.0 / day to 2.5 / day .

My pool is shaded for approx. 1/3 of the day.

 

[durtynacho]

I did the OCLT and went to bed at 6.6, woke up at 6.6, so it really must be the heat. My pool is in full sun pretty much all day, so a loss of 4ppm might be normal for this time of year.

Anyway, at least I know it aint algae! Thanks everyone for the replies.

 

[JoyfulNoise]

My routine daytime temps are 105F and my pool routinely hovers in the high 80's (86-89F) and my pool gets direct sunlight from 8am to 5pm. My daily FC loss is around 2.3ppm/day. I also have an SWG pool and I keep my CYA up at 80ppm.

Your higher FC loss is likely UV related not heat related. Your water would have to be up in the mid 90's for temperature to start playing a significant role.

Increase your CYA if you want to reduce UV loss.

 

[oldguy70]

I did the OCLT and went to bed at 6.6, woke up at 6.6, so it really must be the heat. My pool is in full sun pretty much all day, so a loss of 4ppm might be normal for this time of year.

Anyway, at least I know it aint algae! Thanks everyone for the replies.

I am close with you, I am loosing 3.5ppm per day right now, CYA 40-50 and pool water is 92, full sun for 8+ hours