Using Trichlor pucks to increase CYA

[saml]

For the first time in years my CYA is headed for the low end...30-35. I had a post last year re: CYA levels for sunny pools where a reply was that I could go 60-80 for an all day sunny pool. The recommended level for vinyl using bleach is 30-50. Would it be worth it to increase CYA to say 70 for my situation (once I get through shocking which is this weekend's activity).

If so, I have about 6 pucks left from last year, would it be OK to use them to gain a little CYA or should I just use the pure CYA? I saw another post on the cost for various additions due to their impact on other parameters which need treating but I got a little overwhelmed. I'm just looking for the bottom line or should I not worry about it?

 

[257WbyMag]

If you are wanting to use those pucks up, you can certainly put your pucks in a floater and use them up. Each tablet adds 6 ppm of CYA for every 10 ppm of FC. Now this probably isn't going to get your CYA as high as your are probably wanting it to be, but it will help you some. Use up the pucks and then recheck your CYA level. THen, you can decide how much CYA to add from that point.

As far as 70 ppm of CYA being good, it might be in your case, although that is pretty high for a non-SWG pool. Remember that you will have to run a higher residual FC with that CYA being that high.

 

[frustratedpoolmom]

Remember to keep an eye on your PH and TA and don't let them get too low - the pucks are acidic.

 

[PaulR]

Pool Calculator says 6 of the 3" 8oz pucks will get you about 9ppm CYA. You probably want to put in just 2-3 at a time. My pool is a little smaller than yours; with a cover, two pucks maintains my FC level, without a cover 3 pucks doesn't quite keep up.

Do keep an eye on your pH while you're using the pucks.
--paulr