It is easy to see how cyanuric acid levels can get away from you. It is just so easy to add a few tabs in the floater, or scatter a bag of shock into the pool every week. And the results are close to miraculous: nearly instantly clear, inviting-looking water. It’s so much easier than carrying gallon jugs of liquid chlorine into the backyard. Not to mention those jugs take up valuable space in the truck. And let’s not forget that liquid chlorine has a shelf life, becoming weaker over time.

But think about how the cyanuric acid is adding up every time you add a bag of shock or drop a few more tabs into the water.

Let’s say you start the season with 30 ppm cyanuric acid in a 12,000-gallon pool.

To prevent algae, you plan to shock the pool once a week with dichlor, while keeping a 3-inch trichlor tab in the floater for while you are away.

In this pool, a one-pound bag of shock adds 5.6 ppm, and the tab adds 2.7 ppm cyanuric acid. That’s 8.3 ppm cyanuric acid a week.

If you open the pool on Memorial Day, and close the pool on Labor Day, you’ll have about 145 ppm cyanuric acid, and despite adding all that chlorine, you might even be fighting a battle with algae too!