How often should I test my pool water in Houston?

Twice a week in summer, once a week the rest of the year. Houston heat, rain, and heavy swimming all move the numbers fast — a Monday test can look nothing like a Friday test in July.

What should my pool's chlorine level be?

I aim for 2–4 ppm free chlorine in a Houston summer. The textbook says 1–3, but our sun and swim load burn chlorine fast enough that I'd rather start the week at 4 than end it at zero.

Why does my chlorine test fine but the pool still turns green?

Usually stabilizer (CYA) buildup from years of trichlor pucks. Past a certain point the stabilizer locks up the chlorine so it reads on a test but can't kill anything. The fix is a partial drain and refill, then keeping CYA in the 30–50 range.

Pool Chemistry Basics: The Five Numbers That Actually Matter

You don't need a chemistry degree to keep a pool clear — you need five numbers and a weekly habit. Here's how I explain water balance to every new pool owner.

Pool stores make water chemistry sound complicated because complicated sells test kits and buckets of specialty chemicals. The truth I tell every new pool owner: five numbers run your pool. Learn what they do and you'll be ahead of most of the neighborhood.

1. Free chlorine — the one that keeps you swimming

Chlorine is the sanitizer. It kills algae, bacteria, and everything the kids bring into the pool. The textbook range is 1–3 ppm; in a Houston summer I aim for 2–4, because between our sun and a busy pool, chlorine disappears fast.

My strong opinion after two decades: liquid chlorine is the cleanest way to dose a pool. It adds chlorine and nothing else. Trichlor pucks are convenient, but every puck also adds stabilizer to the water — more on why that bites you in a second.

2. pH — the one that makes everything else work

Target 7.4–7.6. pH matters twice over: it's what your eyes and skin feel, and it controls how effective your chlorine is. At 7.8 and above, chlorine loses a big chunk of its killing power — so a "chlorine problem" is often actually a pH problem.

In Houston, pH mostly drifts up (fresh plaster, aeration from spillovers and water features, salt systems). Muriatic acid brings it down; small doses, retest, repeat. Don't chase it daily — nudge it weekly.

3. Total alkalinity — the shock absorber

Target 80–120 ppm. Alkalinity is the buffer that keeps pH from bouncing around. Low alkalinity and your pH ping-pongs with every rainstorm; high alkalinity and the pH gets stubborn and drifts up. If your pH won't stay put, fix alkalinity first — it's the foundation under the pH.

4. Stabilizer (CYA) — the sunscreen with a catch

Cyanuric acid protects chlorine from being burned off by the sun. Without it, our July sun destroys chlorine in a couple of hours. Target 30–50 ppm.

Here's the catch, and it's the most common problem I find in self-maintained Houston pools: CYA only goes up. Every trichlor puck adds more. After a couple of summers on pucks, pools hit 100+ ppm, and at that level the chlorine reads fine on a strip but is chemically handcuffed — the pool dulls, hazes, then goes green while the owner swears the chlorine is perfect. The only realistic fix is draining part of the water. That's why I keep saying: pucks are fine occasionally (vacation, for instance), but they're not a maintenance plan.

5. Calcium hardness — the slow one

Target roughly 200–400 ppm. Houston fill water already runs hard, and evaporation concentrates it — you top off with more calcium, the water leaves, the calcium stays. Too high and you get cloudy water and scale on tile and inside the salt cell or heater. Too low (rare here) and the water gets aggressive with plaster. This number moves slowly; check it monthly and plan a partial drain-and-refill every few years as it climbs.

The weekly habit that beats all the chemicals

Numbers aside, the routine matters more than perfection:

Test twice a week in summer, once a week otherwise.
Adjust one thing at a time — chlorine first, then pH — and retest before adding more. Half the wrecked pools I see got that way from someone correcting three things at once, twice.
Brush weekly. Chlorine can't kill algae that's protected under a biofilm on the wall. The brush is a chemical multiplier.
Don't stockpile specialty chemicals. A pool with balanced basics almost never needs the exotic stuff on the pool-store shelf. Most of that aisle exists to fix problems the basics would have prevented.

Or let us carry the test kit

Every stop on our weekly service routes starts with a full test and balance — same tech, same day, every week — and we handle the chemicals-only option if you like doing the cleaning yourself. Call 713.462.0762 or request a free quote.