Things You'll Need
Water testing kit
Cyuranic acid is an important element when it comes to maintaining a proper chemical balance in pool water. It's used to stabilize chlorine levels in the pool. If the cyuranic acid level is too low, chlorine dissipates too quickly. If the cyuranic acid level is too high, it interferes with the chlorine's ability to clean the pool and keep it sanitized. Therefore, raising a low cyuranic acid level is extremely important, but be careful not to raise it too high.
Find out the current cyanuric acid level in the pool by using a test kit that measures CYA (cyuranic acid) levels. Not all pool water testing kits measure CYA. If you can't find the proper testing kit, take a sample of your pool water to a pool supply store that does free water testing.
Calculate how much cyuranic acid you need. The target CYA level is between 30 and 50 ppm. If your pool water comes in at much lower than that, then it's time to add cyuranic acid. Most pool CYA water test kits include a chart describing how much cyuranic acid you need to add. If your water test kit does not include a chart, you can find one online (see Resource below).
Add the pre-measured amount of cyuranic acid to a 5-gallon bucket full of hot water. Because cyuranic acid is a very slow-dissolving crystal, it's best to increase the levels in small increments. For example, if you have to add 1 lb. of cyuranic acid to your pool, spread it out over two days and dilute ½ lb. in a 5-gallon bucket each day. The smaller the amount of cyuranic acid, the more quickly it dissolves.
Turn on the filter and pour the dissolved cyuranic acid into the pool at the pool return. You want to broadcast the cyuranic acid into the pool so that it can quickly disperse into the water. Allow the filter to run for at least an hour after adding the cyuranic acid.
Sweep the bottom of the pool. If all of the cyuranic acid crystals did not dissolve, sweep the bottom of the pool to get the crystals off of the bottom and suspended into the flow of water.
Test the CYA level again. If the CYA level is within the acceptable range, then there's no need to add any more. However, if they are still too low, repeat the process each day until the cyuranic acid has reached the proper range.
Stabilized chlorine tablets are mixed with cyuranic acid. While this is another way to increase cyuranic acid levels, be careful. Continuing the use of stabilized chlorine once the CYA levels are within the acceptable range will raise the CYA levels even further.