Crazy question..

[vsat88]

I am unable to measure CYA right now and do not trust the store results. I think I have almost no CYA and cannot tell for sure till I order the reagent. Here gos my question. No matter how much bleach I add I always come back to a measurement of about 1.5 FC and hovers there. Would this happen if I had low or no CYA ? It never seems to want to stay about 4 FC and that is where (I think anyway) it should be if I was at a 40 CYA. Even if I forget to add Bleach one day (and I have more than once) it always seems to be at 1.5 FC..Thanks !!

 

[woodyp]

Sounds like it's either burning off due to low cya or something is eating it. Have you done an OCLT?

 

[duraleigh]

Chlorine is consumed by organics in your pool and UV from the sun. You can only prevent it from going to zero by eliminating BOTH of those things. Chlorine does not become stationary.....it is a consumable item that will deplete to zero at a generally consistent rate.

You likely have a testing error as it simply cannot stay at 1.5 or any other number.

 

[domct203]

............. It never seems to want to stay about 4 FC and that is where (I think anyway) it should be if I was at a 40 CYA. Even if I forget to add Bleach one day (and I have more than once) it always seems to be at 1.5 FC..Thanks !!

You need to stop guessing, and follow the advice and guidelines here.

Your FC target for 40ppm CYA is 5ppm, with a minimum of 3ppm.

http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

Your pool, just like a pet, needs daily care and attention. Letting the FC level drop below minimum for your CYA is inviting algae to bloom, as well as other unsanitary conditions to take over your pool water. Once algae gets ahold of your pool it multiplies faster than rabbits (2 algae spores become 4 become 8 become 16 become 32 etc)

I see you have been a member for a few years, time to buckle down and take a trip to pool school. Read & re-read the ABC's of pool water chemistry as well as how to properly perform an OCLT, and how to properly do and complete a SLAM

Follow these directions to the tee, no shortcuts, no guessing, and I guarantee you will have the clearest, cleanest & easiest to maintain pool you have ever had.

Dom

 

[chem geek]

Something may be wrong because you shouldn't always get the same 1.5 ppm FC reading unless by coincidence the chlorine you add equals the chlorine consumed. Usually if you test within 30 minutes the circulation in your pool will have you measure the addition of what you've added. If there is no CYA, you may lose roughly half the FC amount in one hour though near the surface of the pool or at higher pH it may be somewhat greater loss.

 

[vsat88]

Perhaps I gave bad information, I will try and clear it up. FC never seems to stay at 4,5,6,7..10. PPM through one day, even if I add Bleach each and every day. I did not mean to say that it would not go up or go down below 1.5. What I mean is this..Example..Test AM 1.5 PPM FC. Add bleach..Gos up to 6 PPM. By days end..At 1.5 PPM...Next example..Test PM..Reading is 1.5 PPM FC..add bleach..gos up to 10 PPM FC..10 PPM is too high so I add no bleach next day..That afternoon..Water back at 1.5 PPM FC. I suppose the question I wanted to ask was this...If I have low or no CYA and my pool is algae free with no swimmers could the FC drop from a 10 to a 1.5 in one day ? Could it drop that much in one day due to Sun alone ?

And Dom I will do as you say. I will go back to school. Perhaps I am simply to old recall all of the information that is needed to maintain a pool of this size in a sanitary manner. And Woody, thanks as always I will preform an OCLT tonight and post results. Thank all of you for being willing to help me.

 

[woodyp]

Example for ya': My pool burns off 4 ppm daily with a CYA of 60. Yours could easily drop as much as you say over the course of a hot day, with hotter water if you have zero or NO cya. Especially with the tiniest amount of undetected algae.

 

[vsat88]

Example for ya': My pool burns off 4 ppm daily with a CYA of 60. Yours could easily drop as much as you say over the course of a hot day, with hotter water if you have zero or NO cya. Especially with the tiniest amount of undetected algae.

Thanks, that is what I was trying to ask ! OCLT did not pass last night either so I do have an algae issue as well even though the water is completely clear with no buildup of detectible on the pool walls. It was at a 14 FC at 12:00 Midnight last night and was at a 12 FC this AM..So, I know what to do. I am going to assume the CYA is a 30 and continue at 12-14 PPM all day today and check at frequent intervals then another OCLT tonight. Thank you !

 

[vsat88]

OCLT passes two nights in a row. I did as I said above. It was 5 FC last PM and was 4.8 this AM...Thanks all !

 

[duraleigh]

Nice work!

 

[pooldv]

Yep, that is great!