Who's Eating My Chlorine?

[amboyle7]

I have an above ground, round 13,000 gallon pool.

My CYA is around 40. My pH is around 7.5 I (try to) keep my chlorine around 10. The temperature is around 75 degrees, and my pool gets full sun all day.

This is my question: During the day, my chlorine levels consistently drop between 8 to 10 points. So, in other words, if I start my morning with a chlorine level at 12, by the end of the day, I'm down to 2! IS THIS NORMAL???

I put in a jumbo gallon jug of 6% chlorine just about every night, but I can't get the chlorine to stay in the pool. I've done the overnight test and the levels stay stable overnight.

Regardless, I shocked the Sh** out of the pool this weekend, just to be sure, but I'm still having the same problems maintaining my levels.

So do I raise the CYA even higher? Is there something else possibly zapping my chlorine? Is my pool possessed by cholrine-eating gremlins?

Any advice would be much appreciated!

AMBoyle

 

[jblizzle]

Sounds like gremlins to me .... you are not loosing FC at night because you KNOW what happens if they eat after midnight


You are correct something does not sound right with that large of a drop. And it seems like you are doing everything correctly to try to figure it out. Not dropping at night in the OCLT seems to indicate it is not something in the water. Were you leaving the pump running when doing the OCLT? Is there a different water path used during the day?

So, how confident are you in the CYA level? It would certainly not hurt anything to raise it up closer to 50ppm and see if the daily loss is reduced.

 

[amboyle7]

Yes, I did have the pump running with the OCLT. It's the same water path.

I'm fairly confident in the CYA levels, unless my eyesight is really going goofy on me (which is not unheard of after 50 I guess!). I bought all new chemicals this year just so there wouldn't be a problem with inaccurate readings due to old chemicals.

It has been exceptionally hot this summer, but I don't remember having this much trouble last year. The check-out lady at the grocery store gives me the weirdest looks because I keep buying carts of chlorine! Guess she doesn't have a pool....

Is there any other chemical imbalance that can throw the chlorine out of whack like that? Something I haven't checked for? Dead Zombie Algea?

Thanks for your help. I guess I'll try to increase the CYA and see what happens.

 

[DBfan187]

any healthy people around? cause someone's eating clean!

 

[techguy]

I have been losing a solid 5-6 PPM daily for the past 3 weeks. This is with a CYA of 35, air temps as high as 104F, water in the 80-82 range. I measured the CYA 3 times last night. This is the same result for my CYA as I got a month ago. Sparkly clear water.

I am adding CYA today so I should be losing less by this time next week.