Las Vegas and Henderson pools turn green fast because intense desert sunlight and 100°F-plus heat burn through chlorine in a matter of hours, leaving the water unprotected long enough for algae spores to take hold. The right fix depends on how far the bloom has progressed: a light haze can often be cleared with a strong shock and 24-48 hours of continuous filtration, while a fully green, cloudy pool usually needs a multi-day shock-and-filter cycle or professional intervention. Consistent chlorine levels, adequate stabilizer, and enough daily pump run-time are the three biggest levers for keeping algae from coming back.

Why Algae Grows So Fast in the Desert Heat

Intense, near-constant UV exposure breaks down free chlorine quickly, and without adequate cyanuric acid (stabilizer) in the 30-50 ppm range, a pool can lose most of its chlorine protection within a few hours of direct sun. Warm water above roughly 85°F, common in Las Vegas pools all summer, is also an ideal environment for algae to multiply. Evaporation concentrates minerals and can shift pH out of range, which further reduces how effectively chlorine sanitizes the water, so several desert-specific factors tend to compound at once.

The Main Causes of a Green Pool

Most green pools trace back to one or more of the following: free chlorine that dropped too low for too long, insufficient circulation from short pump run-times, low or absent cyanuric acid stabilizer, phosphates introduced from fertilizer runoff or fill water, organic debris like leaves and pollen providing nutrients for algae, and inconsistent testing that lets small chemical swings go unnoticed until they become a visible bloom. In Henderson and Las Vegas specifically, a single missed week of testing during peak summer is often enough to tip a borderline pool into a green one.

DIY Fix vs. When to Call a Professional

Most green pools can be cleared with the same core process, whether you are fighting a light haze or a fully clouded pool — only the shock dose and timeline change with how far the bloom has progressed.

How to Clear a Green Pool: Step-by-Step

1. Test the water. Test free chlorine, pH, alkalinity, and cyanuric acid before adding anything, so you know your starting point and how large a shock dose the pool actually needs.
2. Remove debris. Skim out leaves, pollen, and other organic matter that feed algae and consume chlorine that should be sanitizing the water.
3. Brush the walls and floor. Brush pool surfaces thoroughly to break up algae before it hardens onto plaster or tile, since chlorine works far faster on algae suspended in the water than on algae stuck to surfaces.
4. Shock the pool. Apply two to three times the normal chlorine dose, or a calculated dose based on gallons and current chlorine demand, ideally in the evening so sunlight does not burn it off before it can work.
5. Run filtration continuously. Keep the pump running around the clock, not just the usual 8-12 hours, until the water clears, and clean or backwash the filter partway through since it will load up quickly with dead algae.
6. Retest after 24 hours and re-shock if needed. If chlorine is still being consumed and the water has not cleared, repeat the shock dose and keep the pump running; most light-to-moderate blooms clear within 24-48 hours this way.
7. Vacuum settled dead algae. Once the water clears, vacuum any algae that has settled on the bottom before it can decompose and cloud the water again.
8. Rebalance chemicals. With the pool clear, retest and adjust pH, alkalinity, and cyanuric acid, then return to a normal chlorine maintenance routine to keep algae from coming back.

Call a professional when black or mustard algae resists repeated shocking, when cloudy water persists past 48-72 hours of continuous filtration, when you suspect an equipment problem is preventing proper circulation, or when the chemical cost of DIY treatment starts exceeding what a service visit would cost.

What It Costs to Fix a Green Pool

A DIY shock treatment typically runs $30-$80 in chemicals for a standard residential pool. A professional green-to-clean service call generally costs $150-$400 depending on severity and whether filter media needs replacing. If the algae bloom caused calcium or plaster staining, which happens more often in Las Vegas due to already-hard water, an acid wash to restore the surface can add another $300-$600. Catching a bloom early, within the first day or two of noticing discoloration, keeps costs toward the lower end of these ranges.

Preventing Algae Year-Round in Southern Nevada

Maintain free chlorine between 2-4 ppm and cyanuric acid between 30-50 ppm so chlorine has both the concentration and the UV protection it needs to last between visits. Brush pool walls weekly to disrupt algae before it can establish a foothold, and run the pump long enough each day, typically 8-12 hours in summer and less in cooler months, to fully circulate and filter the water. Keep pH and alkalinity balanced so chlorine works efficiently rather than being wasted on correcting water chemistry, and if your fill water or landscaping introduces phosphates, a phosphate remover can help starve algae of a key nutrient. Many Henderson HOAs, including communities like Cadence and Anthem, also require pools to be visibly algae-free at all times, making consistent prevention a compliance issue as well as a cosmetic one.

If your pool has already turned green or you’d rather not deal with a summer-long algae fight, call 702Pools at (702) 840-1001 or email service@702pools.com for a free 30-point inspection and a same-week cleanup plan. For more on keeping chemicals balanced between visits, see our chemical balancing guide, browse more local questions on our Pool Service FAQs page, or check HOA-specific notes on our Henderson service page.