You pulled back the cover, or looked out the window after a week away, and the water is the colour of pea soup. You can’t see the steps. The walls feel slimy. Green pool recovery is rarely as hard as it looks, but the order you work in decides whether it takes days or drags into weeks.
Most owners start by tipping chemicals in. That is usually the wrong first move. Below is how we deal with algae in a pool, why the sequence matters, and how to tell when the problem is the surface rather than the water.
Green pool recovery starts with finding the cause
Algae does not appear from nowhere. Something let the water slip. The sanitiser ran out, the pump ran too few hours, a storm dumped leaves and dirt into the pool, or the chemistry drifted until the chlorine stopped working. If you treat the colour without finding the cause, you clear the pool and watch it turn again in a fortnight.
Start with a proper water test, not a guess from the colour. Unbalanced water makes chlorine far less effective, so you can pour in plenty and still lose. Then check the equipment. Is the pump running? Is the filter passing water? Is the timer set to the hours you think it is?
On the pools we build, the electrical board carries a battery-backed timer, so the schedule survives power cuts. A timer that someone changed and forgot about is still one of the most common reasons a pool goes green. Find that kind of fault first and you can clear a green pool once instead of three times.
The order that clears a green pool fastest
There are seven steps, and the sequence is deliberate. Each one makes the next one work better.
Steps 1 and 2: clear the debris, then balance the water
Skim the leaves, scoop out what has sunk, and empty the skimmer and pump baskets. Debris soaks up chlorine, so every leaf left in the water costs you sanitiser.
Next, test and correct the balance. Get the water into range before you add any shock, because chlorine in badly balanced water does a fraction of its job. Skip this step and you will use far more product for a weaker result.
Steps 3 and 4: brush every surface, then shock
Brush the walls, floor, steps and the gap behind the ladder. Algae clings to the surface and shelters there. Brushing breaks it loose so the sanitiser can reach it.
Then shock the water with a high dose of chlorine, following the product label for your pool volume. Doing it in this order matters. Shock without brushing and the algae stuck to the walls survives. Shock before balancing and much of the chlorine goes to waste. Whatever product you use, this is the heart of any algae pool treatment.
Steps 5 to 7: run the filter, keep it clean, then retest
Run the pump day and night until the water clears. Be patient here. Water often looks worse before it improves, because dead algae turns it milky and grey. The filter’s job is to carry that out, and it needs hours, not minutes.
The chemicals kill the algae, but the filter removes it. If the sand bed is tired, dead algae passes straight through and the water stays hazy for days. Old sand also channels, which means water finds a path through it without being cleaned. Our standard equipment package, which we call the Box, pairs a pump with a sand filter and a pump house. When a pool will not clear, we check the sand early.
Backwash more often than usual during recovery. A filter loaded with dead algae restricts flow, and weak flow slows everything else. Once the water is clear, retest, rebalance and hold the chemistry steady so the bloom does not return.
Fix a green swimming pool in place, partly drain it, or empty it
Most green pools recover in place. A few are bad enough that owners ask about draining. This is how the three routes compare.
Treat the water in place
- For: cheapest, keeps your water and your chemistry history, and works on the large majority of green pools.
- Against: slow on a very heavy bloom, and it needs daily attention for several days.
Partly drain and refill
- For: resets water that has become badly over-stabilised or chemically stuck, and saves chemicals on a dense bloom.
- Against: uses a lot of water, and you still have to rebalance the fresh water.
Empty the pool and clean the shell
- For: gives you a look at the bare surface, which helps if you suspect damage.
- Against: a shell is not designed to stand empty casually. Have someone who knows pools look at it before you pull the plug.
Do not drain a pool just because it is green. Algae is a water problem, and water problems have water solutions. A look at the bare surface earns its keep only when the pool keeps turning green despite good chemistry. That points to the finish.
When the pool surface keeps feeding the algae
If a pool goes green again and again while the equipment and chemistry check out, green pool recovery has stalled on the surface. Marbelite is a mix of white cement and marble aggregate. It is a classic, solid finish with a matte look that suits natural stone surrounds. Over time it roughens, stains and develops a texture that algae grips. It typically wants a fresh finish every 7 to 10 years, and a well-built, well-kept pool can reach about 15.
Fibreglass behaves differently. A sound gelcoat is non-porous, so algae has little to hold and the pool is easier to keep clean. That advantage fades once the gelcoat crazes, chalks or blisters, because a damaged surface holds dirt much as worn marbelite does. Either finish can be the cause. Neither one is immune to age.
A new finish is the fix, and it takes less time than most owners expect. Remarbelite and refibreglass each run three to five days. For a 6×4 pool, remarbelite comes to about R18,000 and refibreglass to about R25,000. That is one overall price, and smaller jobs such as a filter sand change fold into it instead of appearing as extras.
Which finish suits you depends on the pool and the look you want. For a closer comparison, read Crispy Pools’ Gauteng comparison of fibreglass and marbelite resurfacing or Northern Pool Services’ summary of the differences. Once the surface is sound again, the pool is far easier to turn blue and keep that way.
Gauteng weather and keeping the water blue
Our summers do much of the damage. Hot, bright weather speeds algae growth and burns through chlorine. A heavy afternoon storm then washes leaves, dust and grit into the water and stirs up whatever already clings to the walls. A clear pool can turn green within days.
Hail adds another layer. Besides the debris, it can chip or crack a surface, and a damaged patch becomes an algae foothold. After a bad storm, do a quick green pool cleanup of the baskets, then check the water and the finish. UV exposure also wears finishes down over the years, which feeds back into the surface problem above.
Prevention costs less than recovery. Test the water weekly, and more often in summer. Keep the pump on for the hours your pool needs, check the timer, and brush the walls even when the water looks perfect. If you would rather not carry that routine, we run maintenance contracts that suit owners who travel or keep busy weeks.
When to call a professional, and what to ask for
Call someone in if the pool does not clear after a full round of treatment. Call too if it keeps turning green with good chemistry, if the filter will not hold pressure, or if you see roughness, cracking, blistering or chalky patches on the surface.
Ask three things. Will they test the water and check the equipment before they quote? Can they tell you whether the problem is the water, the filter or the surface? And if it is the surface, will they put the finish work in writing as one overall price?
If your pool needs green pool recovery or you suspect a surface problem, get in touch for a professional assessment. We handle everything in house, from water testing and filter checks to remarbelite and refibreglass work, so one visit answers all three questions. We normally respond the same day or the following day, depending on how busy the week is.
Frequently asked questions
What is the first step in recovering a green pool?
Before adding any chemicals, you should first clear out any debris like leaves and dirt from the pool. Then, test and balance the water chemistry. Finally, brush all the pool surfaces to dislodge any algae clinging to them.
How long does it take to clear a green pool?
Clearing a green pool can take several days, especially if you have a heavy bloom. You need to run the pump continuously until the water clears, and it’s important to be patient as the water might appear worse before it improves.
When should I consider draining my pool instead of treating it?
Draining your pool is generally not recommended just because it’s green, as algae is a water problem that can be solved with water treatments. You should only consider draining if the pool repeatedly turns green despite good chemistry and equipment maintenance, which might indicate a surface issue.
How often should I test my pool water?
You should test your pool water weekly, and even more frequently during the summer months when hot, bright weather can accelerate algae growth and deplete chlorine faster.
Pool keeps turning green after every clean?
If the water clears and the algae returns, a rough or worn surface may be holding it. Ask for a quote and Trademen Pools will look at the pool and tell you honestly whether it needs a refinish. The team can start straight away.