Green Pool Recovery: Why It Happens and What It Costs to Fix

A green pool is one of the most common reasons South African homeowners call a professional for the first time - often after a holiday, a pump failure, or a few weeks of neglect. Here's what's actually happening and what it takes to fix.

Why a pool turns green

Green water is algae growth, and it takes hold when sanitiser (chlorine or an alternative) drops too low to keep it in check. Common triggers: the pump or filter stopped running (load shedding, a breakdown, or the pool being left unattended), chemical dosing lapsed for a week or more, heavy rain diluted the chemical balance, or a heatwave accelerated algae growth faster than the existing dosing could handle.

What a professional recovery involves

Recovery is more than "adding more chlorine." A typical professional green-pool recovery includes: testing and rebalancing pH and alkalinity first (chlorine barely works if these are off), shock-dosing with a much higher chlorine concentration than routine maintenance, running the pump continuously (not on a normal cycle) to circulate the shock dose, repeated brushing to lift algae off the walls and floor so the filter can catch it, and multiple filter backwashes as the dead algae clogs it. Severe cases (black or very dark green water) may need a partial drain and a manual vacuum-to-waste before the water can be brought back into a maintainable state.

How long it takes

A mild green tint often clears in 24-48 hours of aggressive shock treatment and constant circulation. A fully green or cloudy-green pool typically takes 3-5 days of active treatment before it's swimmable again. Black or severely neglected pools can take a week or more, sometimes with a partial or full drain. Recovery time depends more on how long the pool was neglected than on its size.

What it costs in South Africa

Once-off green-pool recovery is usually quoted separately from a monthly contract, commonly R600-R1,900 per visit, and a bad case can need several visits before it's fully resolved - ask upfront whether a company quotes a flat recovery fee or bills per visit until the water clears. See our pool maintenance cost guide for the full pricing picture, including ongoing monthly service once the pool is recovered.

Preventing it from happening again

The single biggest predictor of a green pool is a maintenance gap - the pump stopped running, or dosing lapsed, for longer than a week. A regular weekly or fortnightly service (professional or a genuine DIY routine) catches a chemical imbalance before it turns into algae. If you travel often or can't commit to a consistent routine, that's usually the point where hiring a professional service pays for itself - see our DIY vs professional comparison.

Ready to get quotes? Compare pool maintenance companies by city, and check our 6-point checklist before you sign with anyone for a recovery job.