Florida sits between 25° and 31° north latitude — roughly the same UV exposure as the deserts of North Africa. A pool in Miami receives more than twice the annual ultraviolet dose of a pool in Chicago. That sunlight is great for swimmers. It is relentlessly hostile to everything the pool is made of: the chlorine dissolved in the water, the PVC of the plumbing, the vinyl of a cover, and the plastic housing of every piece of equipment on the pad.
UV and free chlorine: the CYA story
Free chlorine in water is broken down by UV light — specifically by photolysis of the hypochlorite ion. An unshaded Florida pool without cyanuric acid (CYA) can lose 50–90% of its free chlorine in a single sunny day. This is why CYA is essentially non-optional in outdoor Florida pools: the stabilizer binds loosely with chlorine and shields it from UV, cutting the daily loss to 10–15%.
- Target CYA: 30–50 ppm for residential pools in Florida.
- Up to 60–80 ppm for heavily used rentals or commercial pools where sanitizer loss is a daily battle.
- Above 100 ppm— the stabilizer starts hampering chlorine's disinfection power (“chlorine lock”). Partial drain-and-refill is the only fix.
UV on equipment — the silent aging
- White PVC pipe.Chalks, yellows, and embrittles in 2–4 years of direct sun. Paint with exterior latex or wrap in UV sleeving.
- Pump motor housing.Plastic fans and vent covers crack after 5–7 years of Florida sun. Shading the equipment pad extends pump life substantially.
- Solar covers.Bubble covers degrade fastest — typically 2–3 years under Florida UV before the bubbles start collapsing. Specialty vinyl covers last 4–6 years.
- Salt-cell housing. Clear cell housings cloud over time, which is cosmetic but makes visual inspection harder.
UV sanitation — the industrial story
In the other direction, commercial and some residential pools use UV sanitizers as a secondary disinfection system. Water passes through a quartz-sleeved chamber where a UV-C lamp (254 nm wavelength) inactivates cryptosporidium, viruses, and chloramines. UV does not provide a residual — chlorine still does the in-pool work — but it destroys organisms as they pass the chamber, and it breaks up combined chlorine (chloramines) that cause red eyes and pool-smell.
- UV doesn't replace chlorine. It supplements it.
- Bulbs last 9,000–13,000 hours. Replace on the manufacturer's schedule, not “when it stops glowing.”
- Quartz sleeves foul in hard-water Florida. Quarterly cleaning is normal.
Shading strategies that actually help
Most Florida pools can't be meaningfully shaded — a shaded pool is also a cold pool and a leaf pool. But equipment shading is easy and worthwhile:
- A small roof (“doghouse”) over the equipment pad blocks 80%+ of UV on every component.
- A pergola with shade cloth does most of the same for less money.
- Landscaping well away from the pad provides shade without dropping debris into the pump.
You can't outrun Florida sun, but you can stabilize the chemistry it attacks and shelter the equipment it ages. The pools that last 20 years are the ones where both those choices were made early.