Algae can make you feel like you’re losing your mind: you raise chlorine, the pool looks better, and then the green haze or mustard dust is back next week. We’re breaking that loop by doing something most pool care advice skips, identifying the real source of algae in a swimming pool, not just treating the symptoms. Some pools are simply under heavier “environmental pressure” from pollen, wind, and nearby trees, while others grow algae because of shade, poor circulation, and those stubborn dead spots where sanitizer never truly reaches.

We also get practical about the equipment side of algae prevention. I walk through why a clean, working filter matters so much for chlorine distribution, how seasonal pump runtime often needs a big jump from winter to spring, and why over-backwashing a sand filter can actually hurt performance. If you’ve ever seen low chlorine readings that don’t make sense, worn cartridges or damaged DE grids may be part of the problem.

Then we tackle the chemistry that solves a huge mystery for pool pros and homeowners alike: the free chlorine to cyanuric acid relationship. Using the 7.5% guideline, I explain how a pool can show 10 ppm free chlorine and still grow algae when CYA is very high, especially when trichlor tablets keep pushing stabilizer upward. Finally, we cover prevention add-ons like phosphate remover, enzymes, borates to 50 ppm, and mineral systems like Pool RX, plus the simplest high-impact habit of all: consistent brushing.

If this helps, subscribe, share it with a friend who fights algae, and leave a quick review so more pool owners and service techs can find the show. What’s the one pool on your route that keeps growing algae no matter what you do?

Algae is not inevitable in every pool, so we focus on why certain pools on a route keep getting blooms while others stay clean. We walk through how to pinpoint the real source, then stack prevention tactics that make algae far less likely to return.  
• environmental algae pressure from pollen, trees, and wind-driven debris  
• shaded areas and circulation dead spots where chlorine does not reach  
• filter condition and seasonal runtime as core algae controls  
• sand filter backwashing based on a 10 psi rise  
• the 7.5% free chlorine to cyanuric acid ratio and why “high chlorine” can still fail  
• strategies to avoid runaway CYA from trichlor tablet use  
• phosphate remover and enzymes as algae prevention tools  
• borates to 50 ppm for long-term algistat protection  
• mineral systems like Pool RX to prevent microalgae  
• weekly brushing as a simple, high-impact habit for stubborn pools  

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