Pool Cyanuric Acid (CYA): Chlorine Stabilizer & Ideal Levels
Parameters for Cyanuric Acid.
- Ideal CYA levels for outdoor pools: 30- 50 ppm
- Above 50 ppm is too high; chlorine is less effective.
- Cya Too low: no protection for chlorine; it burns off too fast.
Whatever the level of CYA, multiply by 0.075; that's how much chlorine you should have in the water.
Why is Cyanuric acid used in pools, and what is it?
Cyanuric acid is used in pools because it protects chlorine from the sun. In outdoor pools, it makes your chlorine last longer as long as it is within range. It keeps the chlorine steady throughout most of the pool, so you don't have as many uneven spots of chlorine levels. So, in a way, at the right level it does a better job of keeping away algae than chlorine by itself.
CYA, believe it or not, is made from urea. You have to be careful with CYA, though, because it builds up fast. If it gets above range, it slows down your sanitizer (chlorine) a lot. Because it binds with chlorine. At the right level, it binds with chlorine and keeps it from deteriorating too fast, and lets it do its job.
If there is too much CYA, it binds the same way to chlorine, but it kind of overpowers the chlorine and binds to it too much. Kind of like too much protection, and the chlorine slows down. So now that it slows down, it takes a while to kill bacteria, mean while other bacteria is forming in the pool.
It is always best to keep CYA within range, but if it somehow goes over range. The rule is to keep whatever amount of CYA in the water X 0.075 of chlorine. So algae doesn't form, and CYA doesn't slow down all the chlorine in the water. For example, if your CYA is 60, you should always keep chlorine at 4.5 or higher to prevent algae from forming.
Your CYA may be too high if
- If the pool water is cloudy or there is algae.
- You use chlorine tablets week after week.
- Your pool smells like chlorine.
Chlorine tablets contain CYA, so the CYA levels could get away from you. If your pool smells like chlorine, it could be a sign because CYA is made from Urea, and Urea turns into ammonia.
Ammonia and chlorine mixed together create the chlorine smell. It makes chloramines; when there are chloramines, it means the chlorine is being overpowered. Essentially, chlorine doesn't smell; only when it binds to other products does it smell.
What Causes CYA to Rise?
- Anything that contains trichlor, whether it be powder or tablet
- Anything that contains dichlor, whether powder or tablet
- Anything that says stabilized chlorine in it
Safe CYA Levels By Pool Type
- Outdoor Chlorine Pool 30-50 ppm
- Outdoor saltwater pool 60-70 ppm
- Indoor pool 0-20 ppm
You may ask why the range is a little higher in outdoor saltwater swimming pools. Well, if you think about it, if you have a salt system, where is the chlorine going to come out of the most when the salt cell produces chlorine?
Through the jets closest to the pump pad where the salt cell is. If you have the equipment pad on one side of the pool, the opposite side isn't going to get that much chlorine. Or by the time the chlorine tries to get to the opposite side, it gets burned off by the sun. So that's why CYA is recommended at 60-70 ppm in a salt pool, so it could protect the chlorine while it tries to get to every part of the pool.
Issues if CYA is too high
- Chlorine is less active, which means you need more chlorine to actually sanitize the water.
- Could have a good chlorine reading but still have bacteria in the water because the stabilizer is holding back the chlorine's ability to sanitize.
- Could have algae outbreaks.
- Could cause damage to your pool surface. CYA is acidic.
- Could cause irritation to swimmers
CYA is acidic. It shows up on your alkalinity test, but if you don't know how to account for it, you could lower your PH too low, thinking your alkalinity reading is your true alkalinity. But you haven't deducted CYA from the equation.
Irritation to swimmers. CYA, as we said before, is made from urea. Which turns into ammonia and combines with chlorine. Making combined chlorine. Combined chlorine is what gives swimmers irritation. Itchiness, rashes, etc.
There are three levels of chloramines: Monochloramines, Dichloramines, and Trichloramines. Chloramines start off as monochloramines and progress to trichloramines, which, according to some sources, can cause cancer over a long period of time.
How to Lower CYA, Even in areas with water restrictions
If you want to lower your CYA to a certain number, use the pool level as certain percentages.
For example, if you have 200 CYA and you lowered your pool water level 25% (1/4), you should have lowered your CYA by 50 ppm.
There are certain products on the market that lower cyanuric acid, but the most reliable is removing water.
Two Things you could use if your in an area where there is water restrictions:
- Reverse Osmosis
- Flocculant
If you're in an area where there are water restrictions, you could use reverse osmosis. To lower your Cyanuric acid, there are companies like Pure Water Industries that will come to your house and provide reverse osmosis services. Reverse osmosis will make your water new again and allow you to use fewer chemicals. Your chlorine efficiency will be great after reverse osmosis.
You could also use/add a flocculant to your pool. That will lower CYA by about a 1/3. In case you're in an area where there are water restrictions.
Also, conditioner lasts a lot longer in pools in the colder months. The warmer the water and the higher the chlorine, the less pool stabilizer lasts in the water. Chlorine oxidizes cyanuric acid. Prior to contrary belief, chlorine does oxidize cyanuric acid. A lot of people think just draining, or other treatments to capture cyanuric acid, are the only ways to get rid of it. But chlorine does oxidize it over time, especially in warm water.
Another point is there is a theory that Cyanuric acid sticks to walls. Many well-known pool service professionals deny this. We have come across it a few times. Where we have emptied a pool and refilled and it still has had a stabilizer reading. We are unsure why, but we believe it could be sticking to the walls. We do pool service in Miami so we've come across it several times.
How to get accurate Cyanuric acid test results.
- Make sure your reagents have been kept away from long exposure to sunlight.
- Make sure reagents aren't expired.
- Keep your test instruments clean.
- Retest a couple of times.
If you use test strips, they are very inaccurate and hard to match the colors. We recommend a photometer. A Taylor test kit has a test where, once the water starts getting cloudy in the test instrument, that's your stabilizer level. But that is very hard to tell. A photometer will give you an exact number, which we think is the best way. It is not subjective like the Taylor test kits.
In Summary
Always know your stabilizer levels. Cyanuric acid can be a great help but has to be kept in the right parameters always. As it could very well be a detriment as well if not always kept in range. The best solution is to check it consistently.
FAQ
1. Will Baking Soda raise cyanuric acid?
No, it will not. Baking soda, also known as sodium bicarbonate, is used to raise the alkalinity in your pool. It raises your PH a bit as well.
2. Will shocking a pool raise cyanuric acid?
No, it won't. Actually, it oxidizes cyanuric acid. Over time, it could deplete stabilizer levels, especially in warm water. Studies have been done on this.
3. Does rain raise cyanuric acid in the pool?
No. It doesn't; it could actually lower it because rainwater dilutes it. Also, if the rainwater causes the pool to overflow, it could bring down the Cyanuric acid level.