Why Your Pool Burns Your Eyes in Frisco — It's Not What You Think

Your kids just got out of the pool with red, burning eyes, and the first thing everyone says is "there's too much chlorine." So you back off on the chlorine — add less this week, maybe skip a tablet. And next weekend, the same thing happens. Worse, actually. That's because the conventional wisdom is exactly backward: a pool that irritates your eyes almost always needs more chlorine, not less.

This trips up pool owners across Frisco — especially families in Phillips Creek Ranch, Richwoods, and Lawler Park who are maintaining a pool for the first time and operating on what they've heard rather than what the chemistry actually says. The "chlorine burns eyes" myth is one of the most persistent and damaging misconceptions in pool care, and it leads people to under-chlorinate their pools, which makes every other problem worse.

The Real Cause: Chloramines, Not Chlorine

The chemical that irritates your eyes, turns your skin dry, and gives the pool that sharp "chlorine smell" isn't chlorine at all. It's chloramines — specifically, a compound called nitrogen trichloride that forms when free chlorine reacts with nitrogen-based organic contaminants.

Those contaminants include:

• Sweat — the primary source in residential pools
• Urine — nobody wants to talk about it, but it's a factor, especially with young children
• Sunscreen and body lotion — these introduce oils and chemical compounds that react with chlorine
• Cosmetics and hair products — anything on a swimmer's body enters the water
• Organic debris — pollen, leaves, insects, and anything decomposing in the pool

When free chlorine encounters these nitrogen-containing compounds, it bonds with them to form combined chlorine — chloramines. There are three types (monochloramine, dichloramine, and trichloramine), and it's the trichloramine that becomes gaseous at the water's surface. That gas is what you smell, and when it contacts the moist surface of your eyes, it causes the burning and redness.

Free chlorine at the levels maintained in a residential pool (1-3 ppm) does not irritate eyes. Your eyes have a natural tear film with a chloride concentration far higher than pool water. The irritation comes exclusively from chloramines and, in some cases, from pH being out of range.

How to Test for Chloramines

Your test kit measures two things: free chlorine (FC) and total chlorine (TC). The difference between them is your combined chlorine (CC) — the chloramines.

Combined chlorine = Total chlorine – Free chlorine

If your FC is 2.0 ppm and your TC is 3.5 ppm, your CC is 1.5 ppm. The industry threshold for acceptable CC is 0.5 ppm. Above that, you'll start noticing the smell and the eye irritation.

Most basic test strips only show free chlorine. To properly diagnose a chloramine problem, you need a test kit that measures both FC and TC — the Taylor K-2006 is the standard, or a good digital test kit that differentiates between the two readings.

The Fix: Shock Your Pool (Yes, Add MORE Chlorine)

The solution to chloramine irritation is superchlorination — raising the free chlorine level high enough to oxidize the chloramines and break them apart. This is what shocking does.

To break up chloramines, you need to raise the free chlorine to roughly 10 times the combined chlorine level. If your CC is 1.5 ppm, you need to hit 15 ppm free chlorine temporarily. That's a heavy shock dose, but it's what the chemistry requires.

For a typical 15,000-gallon Frisco pool:

• 1 gallon of 12.5% liquid chlorine raises FC by roughly 8-10 ppm
• For a CC of 1.5 ppm, you'd need about 1.5-2 gallons to reach breakpoint chlorination

Add the shock after sunset — UV destroys unstabilized chlorine rapidly, and you need the full overnight cycle for the oxidation to complete. Run the pump for at least 8-10 hours after shocking.

The next morning, test again. FC should be elevated but dropping back toward normal. CC should be at or near zero. If CC is still above 0.5, the organic load was heavier than one shock dose could handle — shock again that evening.

Wait to swim until FC drops below 5 ppm — typically 24-48 hours after a heavy shock dose.

The pH Factor — The Other Half of Eye Irritation

Chloramines cause most pool-related eye irritation, but pH out of range contributes too. Human tears have a pH of approximately 7.4. When your pool's pH matches that — or is close to it — the water is comfortable. When pH drifts below 7.0 or above 7.8, the mismatch between the water's pH and your eye's natural pH causes irritation independent of chloramine levels.

In Frisco, where municipal fill water tends to come in at 7.8-8.0, pool pH can drift high if not managed. High pH pools often feel "softer" and less irritating than low pH pools, but both extremes cause discomfort. Keep pH at 7.2-7.6 for comfortable swimming.

If your pool's pH is correct (7.2-7.6) and you're still experiencing eye irritation, the cause is almost certainly chloramines. Test CC and shock accordingly.

Why Frisco Pools Are Prone to Chloramine Buildup

Several factors common in Frisco create higher chloramine production:

High Bather Load in Family Neighborhoods

Frisco's demographics skew young families with children. Homes in Starwood, Phillips Creek Ranch, and the developments along Panther Creek Parkway have kids in the pool daily during summer. More swimmers = more organic contaminants = faster chloramine formation.

New Pool Owners Under-Dosing Chlorine

First-time pool owners in Frisco's newer developments often err on the side of too little chlorine, either out of caution or because they associate the "chlorine smell" with excess chemical. This creates a chronic under-chlorination condition where chloramines build up because there isn't enough free chlorine to oxidize them.

Sunscreen Load

Texas sun means heavy sunscreen application — and every swimmer who enters the pool wearing SPF 50 introduces chemical compounds that react with chlorine. In a pool with four kids swimming daily, each wearing sunscreen, the organic load is substantial.

Pollen Season Compounds the Problem

March through May, pollen from Frisco's maturing oak and pecan trees adds organic material to the water that consumes free chlorine and feeds chloramine production. A pool owner who was maintaining adequate FC in winter may find the same dose insufficient during pollen season because the chlorine demand has increased.

Prevention: Keeping Chloramines From Building Up

The best approach is preventing chloramine buildup rather than waiting until eyes are burning to react.

Maintain free chlorine at 2-3 ppm, not the bare minimum. Running at 1 ppm leaves no buffer. When bathers enter the pool and introduce contaminants, the FC drops quickly to zero, and chloramines form before the chlorine can oxidize them. Starting at 2-3 ppm gives you headroom.

Shock weekly during summer. A regular weekly shock prevents chloramine accumulation between swim sessions. Don't wait for the smell or the eye irritation — by that point, CC has been elevated for days.

Shower before swimming. This is the single most impactful habit for reducing chloramine formation. A 60-second rinse with clean water removes sweat, sunscreen, body oils, and cosmetics before they enter the pool. It's a hard rule to enforce with kids, but even a partial rinse makes a measurable difference.

Run the pump during and after heavy swim use. Circulation distributes chlorine evenly and prevents dead zones where chloramines concentrate. If the family swims from 2-6 PM, make sure the pump runs during that window and for at least 4 hours after.

Keep organic debris out of the pool. Skim daily during pollen season. Empty the skimmer basket before it overflows. Every piece of organic matter that decomposes in the water creates compounds that react with chlorine to form chloramines.

What NOT to Do

Don't reduce chlorine when eyes burn. This makes the problem worse — you're removing the very chemical needed to break up the irritants.

Don't add "chlorine neutralizer" products. Some pool stores sell sodium thiosulfate as a "chlorine reducer" for eye irritation. This destroys free chlorine, which is the opposite of what you need. It reduces FC without addressing the chloramines that are actually causing the problem.

Don't drain and refill to fix chloramines. Draining removes chloramines from the water you drain, but fresh fill water will develop the same problem if the underlying chlorine management doesn't change. Fix the cause (inadequate shocking), not the symptom.

Don't assume goggles are the solution. Goggles protect eyes but don't fix the water. If chloramines are high enough to irritate eyes, they're also high enough to irritate skin, and they indicate that your pool's sanitation is compromised. The health risk of inadequate sanitation is more serious than the discomfort of red eyes.

When to Call for Help

If you're shocking weekly and maintaining 2-3 ppm FC but CC still won't drop below 0.5 ppm, there may be a deeper issue — an organic contamination source you haven't identified, a circulation problem creating dead zones where chloramines concentrate, or a plumbing issue allowing untreated water to bypass the sanitizer.

A comprehensive water test (beyond just FC and pH) can identify chloramine sources and unusual chemical interactions. We do this regularly for Frisco families who've been fighting the "too much chlorine" misconception and need a fresh start with their water chemistry.

---

Red eyes after every swim? Hydra Pool Services maintains proper chlorine levels and eliminates chloramine buildup as part of weekly service across Frisco, Plano, McKinney, Allen, Murphy, Parker, and The Colony. End the burning — try us free for 2 weeks →