I'm having a strange issue with CYA level in my 26K gal pool: I am observing a steadily decreasing level of CYA over the past few days via the Taylor K-2006 CYA test.
The recent history of this pool is that I took over maintenance a couple weeks ago and found that it had no detectable CYA level, which neatly explains the phenomenon described by the prior 2 pool maintainers that claimed they couldn't get the pool to retain chlorine. I then raised the CYA to 40 by adding 8.2 lbs of granular CYA to it, performed a 6 day SLAM where I vacuumed to waste several times, and have been keeping the pool at 5-8 ppm FC for the past 5 days. After vacuuming to waste several times, I likely cycled ~20% of the water out of the pool and refilled it using a mix of untreated well water and softened water. The CYA level was 30 immediately after completing the SLAM 5 days ago.
Since completing the SLAM, I have been monitoring the FC loss and it was above 5 ppm / day at CYA of 30. I have added 2.05 lb of granular CYA twice in the past 5 days, with the goal of reducing the FC loss rate. At first, I saw the CYA go from 30 to 40 after adding the first 2 lbs, but since adding the second 2 lbs, the test kit shows CYA *dropping*, which I found very surprising. I tested this morning after adding the 2 x 2 lbs of CYA over the past 2 days, which I would expect to show CYA of 50 (30 + 10 + 10). Instead I'm seeing a CYA of 30. I am reticent to continue adding CYA since I know reducing CYA often requires a partial draining of the pool.
A potentially relevant piece of information here is that I have a Taylor K-2006 kit, which only came with enough test reagent for 6 CYA tests. I ordered a 16 oz refill container of the CYA test reagent and have been using this reagent for recent tests. Since my searches of the forum suggest that it's not possible to suddenly start losing 10 ppm CYA / day, is it possible that this reagent refill I ordered has gone bad? Is there a way I can test if the reagent is bad?
Any insights here are welcome, thanks for reading.
The recent history of this pool is that I took over maintenance a couple weeks ago and found that it had no detectable CYA level, which neatly explains the phenomenon described by the prior 2 pool maintainers that claimed they couldn't get the pool to retain chlorine. I then raised the CYA to 40 by adding 8.2 lbs of granular CYA to it, performed a 6 day SLAM where I vacuumed to waste several times, and have been keeping the pool at 5-8 ppm FC for the past 5 days. After vacuuming to waste several times, I likely cycled ~20% of the water out of the pool and refilled it using a mix of untreated well water and softened water. The CYA level was 30 immediately after completing the SLAM 5 days ago.
Since completing the SLAM, I have been monitoring the FC loss and it was above 5 ppm / day at CYA of 30. I have added 2.05 lb of granular CYA twice in the past 5 days, with the goal of reducing the FC loss rate. At first, I saw the CYA go from 30 to 40 after adding the first 2 lbs, but since adding the second 2 lbs, the test kit shows CYA *dropping*, which I found very surprising. I tested this morning after adding the 2 x 2 lbs of CYA over the past 2 days, which I would expect to show CYA of 50 (30 + 10 + 10). Instead I'm seeing a CYA of 30. I am reticent to continue adding CYA since I know reducing CYA often requires a partial draining of the pool.
A potentially relevant piece of information here is that I have a Taylor K-2006 kit, which only came with enough test reagent for 6 CYA tests. I ordered a 16 oz refill container of the CYA test reagent and have been using this reagent for recent tests. Since my searches of the forum suggest that it's not possible to suddenly start losing 10 ppm CYA / day, is it possible that this reagent refill I ordered has gone bad? Is there a way I can test if the reagent is bad?
Any insights here are welcome, thanks for reading.
