His neighbor, Old Man Henley, who had a pool so clear it seemed to exist in a different dimension, walked over with a plastic bucket. Inside: a tattered, laminated card. "Pool Chemical Cheat Sheet," it read. But it wasn't a list of dos and don'ts. It was a story.
At the very bottom, faded nearly to white, were the last two rules: Never mix chemicals. Ever. Trichlor + Cal Hypo = fireball in your face. Add acid to water, never water to acid. Mark looked up from the sheet. His pool was no longer green. It was a milky, confused blue—the color of dawn after a bad night. He set the filter to run overnight. He put the cheat sheet back in his own bucket. pool chemical cheat sheet
The cheat sheet didn't start with chlorine. It started with a word: Comfort . pH 7.4–7.6: The eye of the needle. Above 7.8, chlorine sleeps. Below 7.2, it eats your skin, your liner, your patience. Mark had poured in shock—bags of the stuff. But his pH was off the charts (8.2, he later learned). The chlorine was present but useless, like a guard dog locked in a soundproof room. The cheat sheet explained: Total Alkalinity is the mattress; pH is the sleeper. Adjust the mattress first (80–120 ppm), then tuck in the pH. He added sodium bisulfate (pH down) and felt the water sigh. His neighbor, Old Man Henley, who had a
He understood now. A pool isn't a bucket of water. It's a living chemistry set. It’s a covenant between pH and chlorine, a war against invisible invaders, a constant negotiation with the sun. The cheat sheet wasn't instructions. It was a map of a fragile kingdom—his kingdom—and for the first time, he knew how to be a decent king. But it wasn't a list of dos and don'ts
Next, a drawing of two ghosts. Free Chlorine (FC): Your knight. 1–4 ppm. Combined Chlorine (CC): The monster your knight has already slain. If CC > 0.5 ppm, you smell "chlorine." That's not chlorine. That's chloramine—the stench of victory rotting. Mark had always thought a strong chemical smell meant a clean pool. The sheet taught him it meant a dirty pool. The smell was the pool begging for more shock to burn off the used-up fighters. He learned the 10x rule: to break chloramines, you need 10 times the CC level in free chlorine. His CC was 1.0. He added 10 ppm of calcium hypochlorite. The next morning, the green was gone. The water was cloudy, but the green was gone.
The day the water turned emerald green was the day Mark realized he’d been treating his pool like a bathtub. He’d been lucky for two summers—dump in a little chlorine, run the filter, swim. But this year, the algae laughed at him. It wasn't just green; it was thick , a viscous bloom that looked like someone had liquefied a golf course.
The next morning, the water was glass. And somewhere, Old Man Henley smiled.