I ask because I got my CYA to 30 at the beginning of the season but it now registers at 0. Granted I had not been checking every week but that surprised me. Granted it has been very hot recently so I have had some evaporation and replacement water and we had lots of rain a few weeks ago. I checked it twice after that reading to ensure that was really the case with same results.
How quickly should I expect to lose CYA?
- Thread starter Vtfanatic
- Start date
Is the pool holding Free Chlorine?
Evaporation will not change the CYA reading. Water dilution or replacement will.
Conversion to ammonia is a risk if FC dropped below recommended levels and rainwater runoff containing soil bacteria entered the water.
Evaporation will not change the CYA reading. Water dilution or replacement will.
Conversion to ammonia is a risk if FC dropped below recommended levels and rainwater runoff containing soil bacteria entered the water.
GOONiE
0
Below is an interesting thread where Chem Geek speaks about CYA relationship. In addition, I remember (can not find the source and may be in this article), in where CYA is lost slowly during the swim season because of the conversion of ammonia. I, on average will loose about 20 ppm during the swim season. Before the SWG, I always started with a CYA of 50, and by the end of the season, I would be down to about 30. Prior to closing, I would bring up to 50, and throughout the winter, my levels would drop to about 30 upon opening. (Weird cycle, but pools are funny). Now with the SWG, I am at 70. Another thing I found is that at TA of 90-100, I had rising PH almost every 4 days because of my rotating heads (this was at lower CYA levels). Now, at a CYA of 70, my PH remains stable, even at 90-100. CYA is not just abut the "Sun", it is also about managing PH levels as well.
You want to rule out ammonia, or at least perform a SLAM and add CYA to the appropriate levels. Unless you had testing error, there should not be this much of a loss in a short period of time. Also, I wait at least 3 days prior to testing CYA when the pool is opened as it has been sitting around all winter long. Please keep us posted!
New Thinking: Chlorine/Cyanuric Acid In Balance - AQUA Magazine
MannyT
0
I lost that amount of CYA having to dump water out of the pool because of constant rain also, atleast 3" of water 4 or 5 times.
A quick update. I bought a test kit for ammonia tonight just to ensure I did not have that issue. Turns out I do not have ammonia which makes me wonder if I did not have it at one point earlier. Anyhow, my plan is to add a few chlorine pucks, add in stabilizer to bring my CYA to 30 and then SLAM if needed. I have a little bit of algae going on as I was away over the weekend and pool was not maintained. Does everyone agree that should be the course of action? Also my CH has been low (150). I add enough recently to bring it to 200 and have enough to bring it to 250. Could that have had any impact to CYA and am I good to go ahead and make that adjustment? Thanks.
Yes and No. You have to neutralize the ammonia by babysitting the pool. Add enough chlorine to bring up to SLAM level and then test 30 minutes later. Add enough until you are holding chlorine. If after the first few hours, you are holding chlorine, then the ammonia has been neutralized and the SLAM process has started. Do not just add to SLAM and think that the chlorine will be there 4 hours later. You have to be diligent in testing. Follow the SLAM instructions and do not veer off.
No impact on CYA, but you may have to wait because of backwashing through the SLAM process. You also will need to plug in your figures through Pool Math and check CSI to make sure you are within guidelines. Plaster pools require higher CH, usually between 300-350, but again check CSI in Pool Math. Thanks!
I'm assuming your adding liquid for chlorination (since you said not maintained). Once your algae/SLAM issue is resolved, and you are in fact using liquid, I would suggest a CYA of at least 50 to retain a chlorine residual if you are not going to be home for a couple days. You can bump your chlorine up a little higher than normal and go away for a weekend and still be above your "min" level for FC when you get back, then you should be able to avoid a repeat situation.
I do usually only add liquid bleach. However speaking from experience, I know that pucks add CYA and since line was already missing CYA I added a few to speed up the process. Once CYA is correct, I will resort to only bleach again.