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The Puripool Process To Lower Cyanuric Acid

When it comes to keeping your pool sanitized, clear and blue, chlorine is the most important chemical that you will use in your swimming pool. Whereas, Cyanuric Acid (CYA), also known as conditioner/stabilizer, helps prevent chlorine loss in swimming pools. As much as this chemical is vital in your swimming pool, it can also be extremely challenging when the levels get too high! During the hot summer months, the sun’s ultraviolet rays destroy free chlorine but having the proper amount of CYA in the swimming pool can prevent that and we hope that this post helps explain why CYA is necessary for your swimming pool and how to lower it when the levels get higher than normal recommended amounts.

In an outdoor pool (indoor pools typically do not require any CYA) with no CYA, chlorine is consumed within the first two hours of sunlight hitting the pool.  CYA serves to protect the chlorine (sometimes called sunscreen for chlorine) and allow it to stick around longer.  However, too much CYA will bind over the chlorine and will not allow it out to work.  We often hear that “I can’t keep chlorine in my pool” when it really is present but unable to break through the grip of CYA.

When it comes to understanding CYA and its effect on your water chemistry the following is the most important:

  • There is a direct relationship to the amount of CYA in a pool and the proper chlorine level. The multiplier to figure out how much chlorine (in ppm) you need is .075   In the case of a pool with 40 ppm CYA, we would take 40 times .075 to get minimum chlorine residual of 3 ppm (we always talk about free chlorine here).  A pool with 80 ppm then would require a minimum of 6 ppm free chlorine as 80 X .075 = 6.  Oftentimes in our industry, we hear that 2-4 ppm Free Chlorine (CH) is good, with no regard for the relationship it has with CYA.  With this simple example, you can see that a pool with 80 ppm CYA and only a 4 ppm free chlorine residual is asking for trouble (algae)!  You must either lower your CYA level or increase your free chlorine to keep a safe and sanitary pool in this case.

Just this past week we filtered a 12,000-gallon swimming pool with CYA greater than 100 ppm which means their FC would have to be greater than 7.5 ppm which over time can be extremely challenging. So, at this point using RO to lower CYA is the best solution. The following was the initial chemistry when we showed up.

Calcium Hardness – 700 ppm

Total Dissolved Solids – 3324 ppm

CYA – Over 100 ppm

After filtering their pool water with our mobile filtration Puripool Process we lowered their water chemistry to the following without draining the swimming pool.

Calcium Hardness – 130 ppm

Total Dissolved Solids – 714 ppm

CYA – 35 ppm

Not only are we efficient in providing excellent water quality but we also can conserve up to 85% of the existing water in the pool. To learn more, please contact us today!