How to Add Cyuranic Acid to a Pool

Cyuranic acid helps to maintain proper chlorine levels.

Most pool owners understand and appreciate the benefits of having the proper amount of cyuranic acid (CYA) in a pool. It not only helps the chlorine to sanitize the pool better, it stabilizes the chlorine so it won't dissipate so quickly. Fortunately, when the CYA level is within the acceptable range, it stays there. It does not fluctuate. The downside to adding cyanuric acid is that you cannot freely toss cyanuric acid crystals into the pool. The crystals must be properly prepared before adding them to the pool.

Things You'll Need

• Pool water test kit
• 5-gallon bucket

Instructions

1. Determine exactly how much cyuranic acid you must add to the pool. Since cyuranic acid does not dissipate as chlorine does, be mindful of how much you add. Removing excess cyuranic acid is a labor-intensive process that involves draining a substantial amount of water from the pool. Most testing kits that measure cyuranic acid levels provide a chart to explain how much to add based on the number of gallons of water in the pool. If your kit did not have such a chart, you can find the calculations online (see Resources below).

2. Pour the pre-measured amount of crystallized cyuranic acid into a 5-gallon bucket of very hot water. Since cyuranic crystals are difficult to dissolve, the hotter the water, the better. After adding the crystals, periodically stir the water to help the crystals dissolve.

3. Turn on the pool filter. The water must be moving before adding cyuranic acid to the pool.

4. Broadcast the dissolved cyuranic acid into the water at the pool return. Pour it directly into the flow of water to help it disperse quickly and thoroughly around the pool.

5. Check for undissolved crystals on the bottom of the pool. Because it does take so long to dissolve, some of the crystals may not dissolve or may become suspended in the water flow. These undissolved crystals will sink to the bottom of the pool. If this happens, sweep the bottom while the filter is still running to return the crystals to the water flow. Allow the filter to run for at least an hour.

6. Retest the cyuranic acid water levels to see if they're in the acceptable range of 30 to 50 parts per million. If not, repeat the process until the cyuranic acid levels are in the proper range.

Tips & Warnings

• Take several days to add cyuranic acid to the pool. It dissolves more quickly if you put a smaller quantity into the hot water. Therefore, if you must add 1 lb. to bring the levels within range, add ½ lb. per day over a two-day period.

References

• About Above Ground Pools: Where Did My Pool Chlorine Go?

Resources

• CSGNetwork.com: Pool Chemical Conditions Calculator