Lowering Cyanuric Acid In Swimming Pools
When CYA levels climb in your swimming pool it can be more challenging to maintain. That’s why we decided to write about five different important things you need to know about it.
- CYA or Cyanuric Acid (also called conditioner or stabilizer) does not stand for Cover Your A$$!! While I am sure that not only in the swimming pool industry but in all professions and walks of life, this acronym does pertain to just that quite often! In this case, it is just the common abbreviation for Cyanuric Acid, an item that has quite the notoriety 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.
- The generally accepted range for CYA is 30-50 parts per million (ppm) in a “normally” chlorinated pool and 60-80 ppm in a salt water pool. There has also been some discussion recently that the optimal range is 8-24 ppm, so you can see that this is a very passionate group with multiple thoughts as to what exactly is the perfect level.
- 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. You can add more if needed.). A “floater” or tab feeder that utilizes 3” tablets or “pucks” of chlorine is often cut with 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.
- The purpose of CYA is not to make you sound smart when you casually toss it out in conversation (“I failed my trigonometry test, but I am more than aware that my CYA is elevated; where is your CYA level?”). In an outdoor pool (indoor pools typically do not require any CYA) with no CYA, chlorine is consumed within the first 2 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 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 (somewhat similar to the Italian Stallion trying to get free from Ivan Drago in Rocky IV).
- There is a direct relationship between 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 a 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 pp 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.
In the past, the only way to remove or lower CYA was to fully or partially drain a pool. Obviously, as the Reverse Osmosis (RO) guys, we never advocate draining and refilling a swimming pool (an exception would be when it is time for a re-plaster), but we know that some people will still opt for this. We understand this, but also wanted to provide some information that you may not be aware of: Reverse Osmosis efficiently removes CYA! It also removes calcium, salt, bacteria, viruses, etc., as well as other yucky stuff that we won’t talk about here.