Challenges of High Cyanuric Acid In Your Swimming Pool

When CYA levels rise in your swimming pool it can be more troubling to maintain. That’s why we decided to write about five different important things you need to know about it and we hope this blog post helps to educate you.

1. Cyanuric Acid (CYA) which is also referred to as conditioner or stabilizer is important but can be challenging.  Depending on who you talk to in the swimming pool industry, some like no CYA, some like some CYA and some like a lot of CYA.  Everybody has a different comfort level and opinion on how much is the right amount. This type of thinking is okay but we feel is important to have some.
2. The generally accepted range for CYA is 30-50 parts per million (ppm) in a normal chlorinated pool and 60-80 ppm in a salt water pool. Please refer to the owner’s manual for our salt system as some levels are different.
3. CYA is added to swimming pools in several different ways. For those who dose their pools with liquid chlorine or use a salt water generator, granular or liquid conditioner is manually added to the pool to get the desired level.  While they both achieve the same thing, liquid conditioner seems to assimilate a bit easier (always add CYA in less volume than you think you need and check the ppm level a week later, as it takes up to a week to fully assimilate into the water because you can always add more if needed but removing it takes a lot more work).  If you use a chlorine “floater” or tab feeder that utilizes 3” chlorine tablets they often CYA and will elevate your conditioner level over time.  While tabs are convenient, that convenience does come with the concern of eventually having too much CYA in the pool.  Granular “shock” products often contain CYA as well, which will increase the amount of conditioner in your pool. Be sure to check the ingredients.
4. To help understand the statement in point #2, in an outdoor pool with no CYA, chlorine is consumed within the first 2 hours of sunlight hitting the pool.  CYA serves to protect the 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 tight hold of CYA. This is why having too much CYA in your pool is a problem.
5. 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 50 ppm CYA, we would take 50 times .075 to get a minimum chlorine residual of 3.75 or 4 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 is good, with no regard to 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. It’s not uncommon for us to pull up to swimming pools will 100 or 200 ppm. Could you imagine why 200 ppm would be so challenging? That would mean you would need 15 ppm free chlorine and this would be a nightmare.

In the past, the only way to remove or lower CYA was to fully or partially drain a pool. Many people in the swimming pool industry say you can also do multiple backwashes but that isn’t gonna do the trick. As a company that uses Reverse Osmosis (RO) filtration, we never advocate draining and refilling a swimming pool.  The bottom line, Reverse Osmosis does remove CYA and does do a great job!  It also lowers calcium, TDS, salt, bacteria, viruses, etc.

If you should have any questions about CYA or how RO filtration can lower it, please contact us today!