Why Algae Keeps Coming Back in Your Pool — and How to Stop It for Good
You shocked it. You scrubbed it. You poured half a bottle of algaecide in.
And still, the green stuff comes back.
Here’s why algae keeps returning and what to do to finally kill it off for good.
🌬️ 1. Your Water Isn’t Circulating Properly
Algae loves dead zones — places with poor water flow like corners, behind ladders, and steps. If your pump or return jets aren’t moving water evenly, algae spores will settle and grow.
🛠️ Tip: Adjust return jet angles and check your pump & filter system.
💧 2. Chlorine Levels Are Too Low (or Unstable)
Chlorine kills algae, but it must be consistent. Let it dip for even 24 hours, and algae can take hold.
Shock treatments help temporarily, but if your pool isn’t holding chlorine, it’s time to test for:
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High phosphates (algae food)
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Low stabilizer (CYA) levels
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Old or weak chlorine tablets
🧽 3. You’re Not Brushing or Vacuuming Enough
Algae forms a slick layer that resists chemicals. Without scrubbing and manual vacuuming, you’re only treating the symptoms, not the root.
💡 Use a stiff brush for walls, especially in shady or low-circulation areas.
💊 4. Your Filter Might Be Clogged or Worn
If your filter media is clogged or old, it won’t trap fine particles, including algae spores.
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Sand filters: Change sand every 3–5 years
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Cartridge: Replace when pressure stays high after cleaning
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DE: Backwash regularly and recharge with new powder
🛠️ Let Labella’s Handle the Algae for Good
Labella’s Pool Service & Supply Inc. will:
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Shock and balance your water
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Clean or replace your filter
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Brush, vacuum, and remove spores
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Set up a weekly schedule to prevent future blooms
We serve Hayward, Castro Valley, Fremont, and nearby cities.
🔗 Related Article:
📘 The Complete Guide to Pool Services in the Bay Area (2025 Edition)
You don’t have to fight algae alone. With proper care, you can enjoy crystal-clear water all season, and Labella’s knows exactly how to get (and keep) it that way.