The Pool Owner's Guide to Winning the War on Algae

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If you've ever walked out to your backyard and found your crystal-clear pool has turned a swampy shade of green overnight, you already know: algae doesn't ease in. It takes over. One day everything looks fine, and the next you're staring at a pool that looks more like a pond.

The good news is that algae is completely preventable, and if it does show up, it's very treatable. Here's what every pool owner should know.

What Algae Actually Is

Algae are simple, plant-like organisms that float in on wind, rain, swimsuits, and pool toys. Your pool water itself isn't the problem — it's the perfect breeding ground when the conditions are right: warm water, sunlight, and low or inconsistent sanitizer levels. Given those three things, algae spores that would otherwise die off multiply fast.

The Main Types You'll Run Into

Green algae is the most common culprit and the easiest to treat. It floats freely in the water, clouding it and eventually coating the walls and floor in a slimy green film.

Yellow (mustard) algae is sneakier. It tends to cling to shaded areas and pool walls, and it's more resistant to standard chlorine levels, so it can survive treatments that would wipe out green algae.

Black algae is the toughest of the bunch. It roots itself into tiny cracks and crevices in plaster, forming a protective outer layer that shrugs off normal chlorine doses. It usually needs to be physically scrubbed before chemicals can finish the job.

Why Algae Shows Up in the First Place

A few things almost always set the stage for a bloom:

• Low or inconsistent chlorine levels, especially after heavy rain, which dilutes sanitizer and washes in organic debris
• Poor circulation, creating dead zones where water sits still
• High phosphate levels, which act like fertilizer for algae
• Imbalanced pH, which reduces how effectively chlorine can do its job
• Dirty filters, which let spores recirculate instead of getting trapped

Prevention: The 80% Solution

Most algae problems come down to a handful of habits:

1. Test your water weekly (more often in hot weather or after storms). Keep free chlorine in the recommended range
2. Run your pump long enough each day to keep water fully circulating — stagnant corners are algae's favorite real estate.
3. Brush the pool regularly, especially steps, corners, and shaded walls, even if the water looks clean. Algae spores can be present before you ever see a bloom.
4. Shock the pool periodically, particularly after heavy use, storms, or a stretch of very hot days.
5. Clean or backwash your filter on a regular schedule so it isn't just circulating the problem.
6. Consider an algaecide as routine maintenance, not just a cure — a little goes a long way as a preventive measure.

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The Bottom Line

Algae isn't a sign you're a bad pool owner — it's just biology finding an opening. The fix is almost always the same: keep water balanced, keep it moving, and don't skip the boring maintenance tasks. A consistent routine will keep your pool looking like a postcard all season instead of a science experiment.- contact a professional like FTG pools if you need some help!!-Contact FTG Pool | Pool Cleaning Company

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