Does chlorine really dissipate this fast?

[shellsingleton]

I'll check out the cya link later, thanks for the advice. I can see consistency is required to help minimize human error.

The FC was 20ppm this morning. I'll remeasure the pool when I get time this afternoon.

edit: moved the equipment stuff to the equipment section...

 

[shellsingleton]

Pool volume is 16,200 best geusstimate.
So, adding 94 oz of Cal hypo to 16,200 gallons water that already has 10 FC should raise it to about 31 FC according to the calculator. It raised it to 24.5 in real life. I'm guessing the CalHypo is starting to lose effectiveness? It was outside, dusty, in their lawn and garden section. No telling where it was stored all winter, as this store has only recently been opened.

So, is a drop from 24.5 to 20 FC overnight enough to indicate the chlorine's being consumed by something?

 

[chem geek]

24.5 to 20.0 ppm FC overnight does mean chlorine is getting consumed, but not as quickly as with an algae bloom (but could be the last remnants of nascent algae). There is some loss that is proportional to the FC level so if you lost 1 or 2 ppm FC I wouldn't think it's abnormal, but 4.5 ppm FC or a nearly 20% drop in FC is more than would be expected. If you can keep the chlorine level up for one more day and see what happens [EDIT]tonight[END-EDIT] then we can go from there. At least now you know how to get a baseline for the FC with this particular Cal-Hypo (i.e. measuring an hour after addtion) so that the measurements will be more accurate.

Richard

 

[shellsingleton]

OK, I'll dose it back up to 30 FC again tonight, do the one hour check, then see what it reads in the morning.
Would you guys prefer that I move my other question regarding the backpressure and vibrations to the equipment section?
Thanks.

 

[JasonLion]

Backpressure/vibration sounds like a completely different issue, so do start a new topic in the equipment section.