Why Is My Pool Water Green?
Green pool water is one of the most common problems pool owners face. While it usually means algae, the underlying cause can vary.
Diagnose My Green PoolThe Most Common Cause: Algae Growth
When pool water turns green, the most likely culprit is an active algae bloom. Algae are microscopic plants that can multiply rapidly in warm water when there is insufficient sanitizer to control them.
However, simply adding more chlorine isn't always the immediate answer. To permanently fix green water, you must understand why the algae was able to grow in the first place.
Underlying Causes of Green Water
Low Free Chlorine
If your free chlorine drops too low, algae can bloom within hours on a hot day.
High Cyanuric Acid
Too much stabilizer (CYA) makes your chlorine less effective, allowing algae to grow even when chlorine tests normal.
Poor Circulation
If the pump isn't running long enough or water isn't moving, "dead zones" develop where algae thrives.
Filtration Issues
A dirty or damaged filter cannot remove organic material, providing food for algae.
Could It Be Metals?
Sometimes, water turns a clear, bright green immediately after adding chlorine. This is often a chemical reaction involving dissolved copper in the water, not algae. Copper can come from well water, copper-based algaecides, or a corroding pool heater.
Don't Guess. Get a Customized Action Plan.
Appearance alone is not enough to confirm a diagnosis. Use Pool Sharks IQ to enter your specific symptoms and test results for a sequential correction plan.
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