How much chlorine does a green pool need to clear up quickly?

Green means algae, and algae eats chlorine

A green pool is an algae bloom, and clearing it takes far more chlorine than routine sanitizing because the algae consumes chlorine as fast as you add it. A normal dose disappears into the bloom with no effect. You have to add enough to satisfy that demand and still leave a killing residual.

How much is enough depends on how bad the bloom is. A faint green tint needs a fraction of what a dark, opaque swamp needs, so the severity of the color is your first gauge of the job ahead.

Keep reading: How do you balance pool water chemistry on a weekly service route?, What is the best way to log chemical readings at every pool stop?, Why does free chlorine keep dropping between weekly pool service visits?. See how PoolTendr helps you pool service route scheduling and chemical logs.

Stabilizer changes the target

The amount of chlorine needed to clear algae rises with the pool's cyanuric acid level, because stabilizer makes chlorine less aggressive. A pool loaded with stabilizer needs a much higher chlorine level to reach an effective sanitizing state than a pool with little stabilizer.

This is why two green pools can need very different doses. Testing the stabilizer tells you what chlorine level you actually have to hit, which is why guessing by pool size alone leads to under-treating.

Filtration and repetition finish the job

Chlorine kills the algae, but the filter removes the dead result, and clearing a green pool is rarely one dose. You shock, run the filter continuously, brush the surfaces, and often shock again until the water turns from green to cloudy blue and finally clear. It is a process over days, not a single pour.

Keep the chlorine elevated until the water clears and holds a residual overnight. If chlorine still vanishes by morning, the bloom is not dead yet and the pool needs another round.

Test, dose to a target, and record it

The reliable path is to test stabilizer and chlorine, dose to the target level the stabilizer demands, and re-test rather than pouring in a guess. Recording what the pool started at and what you added tells you whether the treatment is working across the multi-day cleanup.

PoolTendr logs the pool volume, readings, and each dose you add, so a green-pool recovery becomes a tracked sequence you can see progress on, instead of repeatedly guessing how much more chlorine to throw at it.