Chlorine pucks

[cedougl]

When I opened my pool I did a CYA test. The CYA is down to 25, due to draining water before closing our pool last season, and adding water this season. So, I would like to raise CYA to about 40.

I am using liquid bleach to regulate my FC levels, but I am also using a chlorine 3" puck to slowly increase CYA. Does anyone know roughly how much one chlorine puck will raise CYA in a 19,300 gallon pool? I can keep doing a CYA test after each puck dissolves, but that will take a lot of solution from my test kit. I was wondering if anyone knew approximately how many pucks I would need to use to raise the CYA level from 25 to 40.

Thanks
Chuck

 

[BoDarville]

Pool Math has your answer. One 8 oz. trichlor puck will raise CYA by 1.7 ppm. You will need about 9 pucks to raise CYA from 25 to 40 in your pool. It'll take a while to dissolve 9 pucks. In addition, pucks move several parameters. In addition to increasing FC and CYA, pucks also tend to lower pH. For these reasons, we recommend using granular CYA (sometimes marketed as stabilizer). You will need about 40 oz of granular CYA to reach your target level - and you will get there much faster than by waiting for 9 pucks to dissolve. Add the granules into an old gym sock or similar implement and place it in the skimmer. Run the pump until the granules dissolve - it may take a day or two. To hasten the process, give the sock an occasional squeeze. Note that it may take 5-7 days for the newly-added CYA to appear in test results.

 

[cedougl]

Thanks for the detailed reply! Very helpful.

I do have some stabilizer that I dissolved in a bucket with hot water last season. It has been sitting in a covered bucket all winter. Would that still be good to use? I was thinking of using the pucks because I had some left over from last season that I needed to use up.