Above Ground Pool Chemicals 101: What Those Numbers Mean and Why They Matter

Tired of cloudy water or surprise algae in your pool? You’re not the only one. Most pool problems come down to one thing—unbalanced water chemistry. The good news? You don’t need to be a chemist to fix it.

All you really need is a basic understanding of a few key numbers—like chlorine, pH, and alkalinity—and how to keep them where they should be.

Why Pool Water Balance Matters

When your water is off, everything else starts to go wrong. You might get green water, foamy bubbles on the surface, or that strong chlorine smell everyone hates. It’s not just annoying—it can damage your pool and even cause skin or eye irritation.

At S Kay Pools, we’ve been helping people with this stuff for over 38 years. Whether you're brand new to pool care or just want fewer headaches this season, understanding the numbers below will help you keep your water clean and clear.

1. Free Chlorine (1–3 ppm)

Free chlorine is your pool’s main defense against bacteria and algae.

• Too low? Germs and algae take over.

• Too high? It can irritate skin and eyes.

Keep it between 1 and 3 parts per million (ppm). Granules or liquid chlorine can raise levels fast. Use test strips or a drop test to check it at least once a week—more often during hot weather or heavy use.

2. pH Level (7.2–7.6)

pH shows how acidic or basic your pool water is.

• Low pH = Corrosive water that can damage liners and equipment.

• High pH = Chlorine becomes less effective.

The sweet spot is 7.2 to 7.6. Use a pH increaser if it’s low or a reducer if it’s high. Always run your pool pump while adding chemicals and test again the next day.

3. Total Alkalinity (80–120 ppm)

Alkalinity acts as a buffer for your pH. When it’s off, your pH becomes unstable.

• Too low = Wild pH swings.

• Too high = pH gets stuck and hard to adjust.

Target range is 80 to 120 ppm. We carry both alkalinity increaser and reducer to get it right. Just follow label instructions and test again after 24 hours.

4. Cyanuric Acid (30–50 ppm)

Cyanuric acid (stabilizer) protects your chlorine from the sun.

• Too little = Chlorine disappears in hours.

• Too much = Chlorine becomes sluggish and stops working well.

Keep levels between 30 and 50 ppm. If it’s too high, you may need to drain and refill part of your pool to bring it down.

Bring a Water Sample to S Kay Pools

Keeping your pool balanced doesn’t have to be a hassle. At S Kay Pools, we stock the right chemicals, test kits, and expert advice to help you stay on top of it all.

Bring in a water sample, and we’ll tell you exactly what you need—no pressure, no guesswork.