If you live in Chandler or the surrounding Phoenix metro area, and you have a swimming pool, you may not have heard of Cyanuric Acid (CyA), but you need to know about it. The CyA level in your pool is extremely important to the health of the water and well being of your swimmers.
If you were to head to your local pool store you will not see CyA on the shelf, at least that is not what it is called. You ould see it called chlorine conditioner or stabilizer. These are the commercial names for CyA.
What is CyA and why do we need it in our Chandler Pool?
If you were to take a gallon of liquid chlorine and dump it into a 10,000-gallon pool on a July afternoon in Chandler, that amount of chlorine has enough active ingredients to raise the chlorine level of your pool by about 10ppm (parts per million). The problem would be, a few hours later the UV rays of the sun would be so strong that most of that chlorine would be gone.
CyA helps stabilize the chlorine so it does not burn off so quickly. CyA will wrap itself around the chlorine and act as a buffer. CyA will bind and loose to the chlorine particles to allow it to be released as needed to disinfect the contaminants in the pool water. So CyA is something you need in your pool, especially if you have an outside pool in the Chandler desert.
I have CyA in my pool, so am I good?
Well maybe. It depends on how much CyA you have in your pool. Like chlorine, CyA is measured in parts per million. If your CyA level is too low, below 30ppm, chlorine likely will be burnt off quicker than you would like. If CyA is too high, over 100ppm, then it will do too good of a job and the amount of chlorine you need in your pool to properly act as a disinfectant will be much higher than you want.
The EPA recommends a chlorine level to be 2-4ppm. The CDC recommends a chlorine level of up to 10ppm. Most pool professionals recognize the EPA level as much lower than it needs to be. But we also recognize 10ppm as a higher range than we shoot for. During the Chandler swim season we tend to keep our pools at a 4-8ppm range, knowing as long as it is 2-10 it is healthy enough as long at the CyA is at a good level as mentioned above.
So how much chlorine do I need? CyA has the answer
All agencies agree that for chlorine to be effective it needs to be at 7.5% of the CyA level or 5% of the CyA level if you have borates in your pool as an algistat. This is something we highly recommend. Most pools do not have borates, so the level is 7.5%. Meaning if your CyA level is at 100, your chlorine level needs to be at 7.5ppm to do its job and keep the water safe. If your pool is like many pools in Chandler and has a CyA level of 150, then your chlorine level needs to be at 11.25. This is higher than the CDC upper recommended limits and nearly 3x higher than the EPA recommendation.
Measuring CyA
CyA above 100 becomes very hard to measure. Most test kits only go to 100 or 120 ppm. So if you take a water sample to Leslie’s using their Taylor test kit, your CyA could be 300 and their kit will only measure to 100 so they will say 100. You need to ask them if it is 100, or higher. While they may not be able to tell you what the number actually is, they can tell you it is much higher than 100.
How did CyA get so high in my pool?
When a new pool is started up conditioner needs to be added, with a goal of bringing the Cy up to about 30-50 or 40-80 in a salt pool. Once the CyA reaches that level, we have it where we want it. That level will not change unless we add more conditioner to the pool.
Most non-salt water pools will use chlorine tabs to help maintain a residual chlorine level in the pool. If we have a proper chlorine residual level, the chlorine will do its job and properly sanitize the pool water. These chlorine tablets are needed during the hottest months in Chandler. The problem is these tri-chlor chlorine tablets are about 50% chlorine and 50% stabilizer. This is called stabilized chlorine.
Every 3″ tablet will add about 1.5ppm of CyA to a 10k gallon pool. So if you use 4 tabs a week for the month of July your CyA level in your pool will raise about 24ppm in a month. In the summer it is easy for a pool to go from 40ppm to over 100ppm just by the use of chlorine tabs.
What to do when your CyA rises
There is an added benefit of adding more CyA to a pool from 0-to-50. Once your pool hits 50 there is no added benefit at all as it rises from 50-100. Just remember, you need to keep your chlorine level at 7.5% your CyA level or 5% if you are using borates.
There are states that require commercial pools to not use CyA. Most states require a commercial pool to be drained when the CyA level reaches 50ppm. While there are no such requirements for residential pools because they have nowhere near the bather load in a residential pool, we can learn from them how important they really take the issue of high CyA.
The only way to effectively lower CyA is by diluting the water. Meaning draining out the old water and adding in new water to replace it. There are some products that claim to lower CyA levels, but from our experience, they are hit and miss in their effectiveness and are very expensive to use properly.
How to lower CyA
So we know we need to lower the CyA in our pool, and we know to do that we need to dilute the water. There are a few rules of thumb that Big Family Pools uses with our clients.
When we have a new client, if their CyA is over 100ppm, we recommend a complete drain and refill of the swimming pool. If the CyA is above 150 we recommend a drain and acid wash. We have found CyA will seep into pool plaster and into the bonding materials in pebble pools. A pool could be at 200-300 CyA, be drained and refilled, and a month later already be at 100 CyA again.
Once we have drained and refilled a pool we work to ensure we manage the CyA and below we will give you some tips on how to prevent your CyA level from increasing so quickly. Once we have fresh water and are servicing the pool when the pool gets back to pt close to 100ppm we recommend doing a 2/3 drain and refill of the pool. We know the water is not super old because we had done the drain in the past so we find this saves money by preventing a full drain and it lowers the CyA to a level that can be managed again.
On a non-salt pool, this may be a 2-year cycle. For many non-salt pools this very likely would be a 6-12 month cycle, but we work to extend this period as much as possible.
How to prevent a yearly draining because of CyA
So you now know if chlorine tablets are used in your Chandler pool, the CyA level will increase. You also know that a high CyA level is not good for sanitation and you don’t want to keep your chlorine level at an 11-15ppm level to counter the CyA. So how do we extend the life of the water and keep the CyA level in range for as long as possible?
For non-salt cell pools, we use liquid chlorine and cal-hypo shock along with the tri-chlor tablets over the course of the year. **WARNING cal-hypo is an extremely flammable compound and should never touch or come into contact with any other chemical. Just Google ‘cal-hypo and Coke’ and see the reactions that can happen. We use tri-chlor tablets when the temperature of the water reaches 75-80 degrees in conjunction with liquid chlorine. Once the temperatures drop back down below 75-80 degrees we remove the tabs from your pool (unless CyA is already over 100, in which case they are likely needed to maintain a proper residual).
Once temperatures do fall below 75-80 degrees and chlorine tabs are removed we use liquid chlorine to maintain the chlorine level and if shock is needed we will use cal-hypo, not tri-chlor or di-chlor shock. All chlorine adds something to the pool. Liquid chlorine adding a little salt to the pool is the best alternative followed by cal-hypo which will add a little calcium to the water.
When temps begin to rise again we will add the tri-chlor chlorine tablets back into the pool and continue to also use liquid chlorine with the least amount of tabs possible to maintain a proper residual level. If your CyA level is 40, 7.5% of Cya is a 3, which is a lot easier to maintain than when your level is over 100 and you need a 7.5+ chlorine level.
I will be honest with you, most pool companies do not do this. We are different. How do I know? Over 90% of the pools we take over from other pool companies have a CyA level over 150, many being over 300. In our opinion, this is the biggest mistake most pool companies make. It is something we require from all our clients as we will not be responsible for the water of a pool where we need to keep a chlorine level of over 10 to keep the water safe. This is a health risk to the swimmers and a liability issue for the pool service providers.
If you have any questions or want to know what your CyA level is, please call or text us at 480-331-5331 or follow us and message us on social media @BigFamilyPools.