Can't seem to increase CYA

Jump to latest Follow Reply
tenderfoot

tenderfoot

0
Bronze Supporter
Aug 10, 2017
131
North/TX
I used the Tf-100 kit and measured a CYA level somewhere between 30 and 40.

I am targeting a level of 70, so poolmath told me I needed 4 lbs 11oz of dry cya.

I added 4 lbs of dry cya (Clorox brand) to a sock placed in the skimmer.

It's been more than a week since it all dissipated so I measured today and it's only gone up slightly, closer to the 40 mark.

It did rain cats and dogs around here the past several days could the rain have washed the addition all away through the overflow drain!?!

I really need to get a reliable measurement for CYA and I know the pool stores aren't recommended for any readings, what other choices are there?

I am afraid my reading is not right (either because I am doing something wrong or reagent is bad) so I don't want to add anymore CYA and endup with a high concentration of it...
 
I think it washed out the overflow pipe. I did the same a few days ago. Started with 55 and added enough to go to 65. Then it rained the next day and I ended up at 50.
 
Did u backwash ? If you suspect it was drained out /diluted I would add enough to raise it 10 or 15 ppm via sock in front of a return then re test in a day or two & proceed from there.
 
It did rain cats and dogs around here the past several days could the rain have washed the addition all away through the overflow drain!?!
Click to expand...
Probably not. Did you allow the pool pump to THOROUGHLY mix in the new rainwater with the rest of the pool. It is very likely you may have not gotten an accurate sample.

Here's what you can rely on with almost dead certainty.

1. The reagent doesn't go bad. You should keep it reasonably fresh but it doesn't go bad.

2. If you calculated your CYA dosage correctly (re-check yourself), then the CYA is in there regardless of your test result

3. The CYA itself is a pretty inert product and doesn't go bad, either.

4. Please, please stay out of the pool store for testing. The results are bogus more often than not.
 
  • Like
Reactions: MikeTX and Mdragger88
Thanks all!

@Mdragger88 : No, I did not backswash. I have been avoiding doing that again this year until I get the CYA level correct, as well as the procedure to get it there. :)

@duraleigh : Thanks. Ok, so I understand it is unlikely it washed away. It's been 2 days since it last rained and I run the pump for about 8.5 hours each day, so I'd expect that is enough for all the rain water to have mixed with the original pool water. I collect a sample from about arms length deep on the shallow end. But, I am willing to try other procedures. I am going to dive to the bottom of the deep end, grab a sample and see what that reads! :) I will post back later today.
 
  • Like
Reactions: Mdragger88
If you added cya at the skimmer it went straight to your filter. There is a good possibility that some of the cya is still in the filter and has not circulated. As duraleigh noted, as long as the calculation is correct as to the amount added, the cya level is increased. It may take a while to pass through your filter to show up on a test.
 
  • Like
Reactions: Mdragger88
Ok, thanks. I dove in to the deep end and collected a water sample from the bottom.

The CYA reading for this sample came in at 50. I did it twice and got the same result. That makes me feel a bit better. I will wait another week and test it again before adding any more of CYA. Thankfully no rain for the next week or so.
 
  • Like
Reactions: Mdragger88
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply