CYA Increasing Over Time

[Slappster]

Hello All,

As a newbie, I have been testing my water on a weekly basis to include pH, Alkalinity, Free and Combined Chlorine, CYA, Hardness and Salt levels utilizing a Taylor K2006-S test kit. I have learned on a general level, how my pool reacts to our environmental factors, etc. I have a good understanding of the chemistry changes, how long they take to occur, etc. in order to maintain the chemistry as close to the recommended ideal range as possible. But I have now come across an issue that I can't quite figure out and therefore, don't know how to correct it.

At the beginning of this season, I established the CYA (stabilizer) levels to the 30-50 ppm range. It held steady over the course of the hotter summer months, but has recently (over the past two to three weeks), has slowly increased up to the 80-100 ppm range. I add Baking Soda about every three weeks or so to bump up to alkalinity to the upper end of the ideal range of 80-100, and use muriatic acid to lower the pH on a weekly basis. Other than that, I add nothing. I use my Chlorine Generator to maintain the free Chlorine around 2-5 ppm mark with no issues.

I have read other threads on here about how CYA reacts and changes, but I can't find one that may explain this type of increase and what I can do to correct it.

Any help from the Jedi masters will be appreciated.

 

[Texas Splash]

I've not heard of seen any discussions that attribute CYA increase to anything other than the use of tablets/pucks, bags-of-shock, etc. However I will say that as a SWG pool owner, your CYA "should" be between 70-80. Any chance you actually increased it as directed and simply forgot?

 

[chem geek]

Adding baking soda and then adding acid is a waste of money. You should be targeting a lower TA level to get out of that vicious cycle. I don't know where you are getting the "ideal range" of 80-100 and you should not be targeting the high end of that anyway. The Recommended Levels for an SWG pool is a TA of 60-80 ppm.

 

[tim5055]

Using a K-2006 you should be able to get closer than CYA "ranges" you are giving.

Without accurate testing we really can't give you answers. If your CYA is really 80+ your chlorine level is low and NEVER should be below 4 at 80 and even higher as your CYA goes up.

Have you seen this: Pool School - Chlorine / CYA Chart

 

[Slappster]

Thanks for the response. I used the ideal range as shown in the APSP recommended water chemistry guidelines as shown in the K2006-S booklet. I have never seen a separate guide just for an SWG pool. And you are right, it is rather vicious....I will check out your provided link. The other thing I did differently tonight when performing the CYA analysis, I performed it outdoors in the shade to see if the readings would be different than those normally performed in the garage under the overhead fluorescent lights. I performed it three times wit a reading of 70 ppm versus the 80-90 I read in the garage. I will continue to do so. Again, thanks for you advice - work smarter, not harder.

I will also lower the TA to the recommended levels and then monitor closely. Next season, I plan on incorporating borates into the mix to help with the pH.

 

[JoeSelf]

CYA test should be done with full sun at your back. Tube held from the top at waist level. There is a video showing how to do this
https://www.youtube.com/user/tf100testkit?feature=results_main