Green Algae
Green algae is the most common pool algae species, causing water to turn green or teal and surfaces to become slippery.
Definition
Green algae is the most common pool algae species, causing water to turn green or teal and surfaces to become slippery.
Typical Values: Kill dose: 30 ppm FC (active bloom); Maintain 1–3 ppm FC to prevent
In Plain Language
Green algae (Chlorophyta) is free-floating in the water when first blooming and deposits on surfaces as it matures. It is killed by maintaining adequate free chlorine but establishes a biofilm that must be physically brushed before shock treatment to allow the chlorine to penetrate. Green algae turns grey-white when killed — this dead matter must be filtered or vacuumed out.
Why It Matters
Green algae is the most common pool emergency. Knowing the correct treatment protocol prevents weeks of ineffective treatment.
Typical Values
Kill dose: 30 ppm FC (active bloom); Maintain 1–3 ppm FC to prevent
Last reviewed: 2026-06-01