Going through 5ppm FC / day?

[RonsPlc]

My pool seems to be eating Chlorine to the tune of close to 5pmm per day... is this normal?

My numbers for today were as follows...

7AM

FC - 7.2
CC - 0
PH - 7.4
TA - 100
CH - 60
CYA - 50
Temp - 75f

6PM

FC - 2.4
CC - 0
PH - 7.4
TA - 100
CH - 60
CYA - 50
Temp - 81f

The temp is the water temp, not the air.
According to Poolmath, I needed to add another 120oz of 8.25% bleach to get it back up to 8ppm.
I have had 0 drop in FC during the overnight hours.
I started out with less than 20ppm CYA last week, and added some on tuesday per poolmath, and am now reading 50. I had thought that once I got the CYA in there, I should end up with less loss due to the sun, but I'm going through the same... if not a bit more to hold the higher FC levels that 50pmm CYA needs.
I run my pump 24/7 on low (if that makes a difference).

Am I missing something?

 

[Texas Splash]

By any chance have there been any significant changes in water (i.e. rain water exchange/fill)? Any unusual load in your pool that may have caused the FC to work harder than expected (i.e. lot of swimmers, any tree debris, etc)? Just trying to eliminate any obvious causes since your test numbers do look quite solid.

 

[RonsPlc]

The weather was 97f and sunny today, the only person in the pool was my wife floating around for an hour or so this morning (She also vacuumed the pool through the filter).
I have not had to add any water to the pool since the last backwash (yesterday).
The pool is crystal clear (no debris).

 

[Texas Splash]

Others should chime-in shortly, in the meantime, consider reading this link about a previous thread there in AL:
Daily FC loss

Check back to see if any other TFP'ers have replied.

 

[woodyp]

How are you testing----what test kit?

 

[RonsPlc]

I'm using the K-2006 test kit that I have listed in my signature.

 

[RonsPlc]

ok... having gone through 120oz/day of 8.25 for the past week, I have decided to try raising my CYA to 60, and see if I end up with better FC numbers throughout the day. Hopefully the CYA will do its job, and I end up using less bleach.

 

[AimeeH]

Have you considered doing an overnight chlorine loss test to rule out yet unseen algae?

 

[woodyp]

I'm willing to bet that at BEST...........you only reduce your FC loss by 1ppm. I'll be more than interested to know.

 

[Jkpharm]

Hmmmm, just coming off a SLAM, I was excited to have "only lost" 4ppm from 530AM to 9PM. Maybe I shouldn't have been so jubilant?

 

[RonsPlc]

I have had NO overnight loss for the past 2 weeks (I test every morning, and evening), so I know that it's the sun that's doing it, plus the fact that I have had 0 CC for the same time period clinches the fact that I don't have any algae.
Unless I'm missing something, which is always possible.

 

[chem geek]

You can do an OCLT with the pump running at night to confirm that the consumption isn't something related to circulation such as in the filter or piping or some system that is only on during circulation (e.g. ozone or UV). If the OCLT passes, then you are right that it's related to sunlight so the CYA test reading is suspect or something very weird is going on.

 

[RonsPlc]

My pump runs on low 24/7 during open season, and I get 0 loss overnight ... am in the process of SLOWLY bumping my CYA up. I have some trichlor tabs left over from last season... I'm using them to bump the CYA, AND hold FC for me.

I'll report back once I reach my 60 mark for CYA, and let you know what my results are