What is Cyanuric Acid?
Cyanuric acid (CYA) is known as stabilizer/conditioner for your swimming pool. It is used to reduce the rate at which free available chlorine is lost to the sun's ultraviolet rays. Maintaining the proper CYA level is vital to prevent the loss of chlorine as having too much can actually bind up chlorine and prevent it from functioning correctly.
Is Cyanuric Acid dangerous?
Cyanuric acid is an acid although it is a weak acid. There are no indications that CYA is harmful if used in the proper recommended amount.
How do I detect and test high CYA levels in my pool?
CYA Pool Water Test Kit

Cyanuric Acid Test Kit

Testing the levels of CYA (cyanuric acid) is typically done using a drop based test kit. CYA levels should be in the 30-50 ppm range for most all swimming pools (indoor pools do not need CYA, as they do not suffer from degradation from the sun like outdoor pools).

High CYA levels can also be detected when you see some purple scaling on your pool tile.

How can I lower Cyanuric Acid in my pool?
When CYA levels are too high in a swimming pool it is recommended to drain the pool. Any time that you remove water from a swimming pool you run the risk of ruining the interior finish.
Can I lower Cyanuric Acid levels in my pool without draining it?
Mobile filtration using Reverse Osmosis (RO) filtration allows residential and commercial swimming pool owners an opportunity to recycle their existing swimming pool water. RO lowers calcium hardness, total dissolved solids, and cyanuric acid without draining the swimming pool. You are left with cleaner water than a drain and refill can provide in your swimming pool, and it is extremely environmentally friendly.
Puripoolâ„¢ Process