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The Field Guide to Identifying and Treating Pool Algae

Algae doesn't always look like algae. This guide helps you identify green, mustard, and black algae by their key signs, treat each one with the right approach, and build habits that keep it from coming back.

See the key signs, common locations, and difficulty level for green, mustard, and black algae
Get step-by-step treatment protocols for each type, from brushing technique to chlorine shock levels 
Learn the prevention checklist that keeps chlorine, pH and circulation working against algae before it starts
Understand why dead algae won't clear on its own, and what to do after treatment

Peek Inside: What You’ll Get From The Guide
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Type-by-Type ID:

Spot green, mustard, and black algae by their exact signs, common locations, and treatment difficulty.

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Step-by-Step Treatment:

Follow the brush-shock-clean sequence built for each algae type, with product and dosing guidance.

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Prevention Checklist:

Keep chlorine, pH, and circulation dialed in so algae doesn't get a second chance.

Make Cleaner, Clearer Water Possible
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Know Your Algae by Texture

All algae share one trait — biofilm makes them slippery or slimy. Learn what separates a fast-spreading green bloom from stubborn black spots rooted in plaster.

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See Why CYA Matters for Mustard Algae

Mustard algae can return quickly after brushing if CYA and pH aren't in range first. Learn the target range before you treat.

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Know When Dead Algae Isn't Gone

Killing algae is only half the job. Learn why dead algae has to be filtered, vacuumed, and removed — not left to disappear on its own.

The Real Reason Algae Keeps Coming Back

Don't assume a shock treatment is the whole fix. This guide shows you how to identify the algae type first, treat it with the right method, and clear the dead algae after, so it doesn't reappear in a week.

Your Questions, Answered