Green pool water in Mallorca: fix it in 48 hours
Green pool water is the most common pool emergency on Mallorca, and in summer heat it can happen in just 48 hours. The good news: caught early, you can fix it yourself in one to three days. Here is the exact process our vetted maintenance professionals use, plus how to stop it happening again.
Key takeaways
- Green water is algae: low chlorine plus heat, and above 28 degrees it can take over in 48 hours
- The fix: correct pH to 7.2, shock chlorinate at dusk, filter 24/7, brush daily
- Never swim in green water: infection and visibility risk
- Prevention costs 150 to 250 euros a month in season, one rescue costs 100 to 200 euros plus a lost week
Why pools turn green on Mallorca
Green water means algae, and algae blooms when three things line up: too little free chlorine, warm water and poor circulation. Mallorca pools regularly exceed 28 degrees between June and September, which doubles algae growth speed compared with mainland spring temperatures. Add a filter that has not been cleaned since winter, or a pump running only a few hours a day to save electricity, and the water can flip from clear to green over a weekend.
Fix it in 48 hours: step by step
1. Test and correct the pH
Aim for 7.2. Chlorine loses over half its power above pH 7.8, so shocking a high-pH pool wastes product. Use pH minus and retest after two hours.
2. Shock chlorinate
Add rapid-dissolve chlorine at two to three times the normal dose, in the evening so the sun does not burn it off. For a standard 8×4 pool that usually means 300 to 500 grams depending on product strength.
3. Run the filter non-stop
24 hours a day until the water clears, backwashing the sand filter whenever pressure rises. This is where most DIY attempts fail: four hours of filtering will not clear an algae bloom.
4. Brush and vacuum
Brush walls and floor daily to break the algae film so chlorine can reach it, then vacuum the dead algae (grey dust) to waste rather than through the filter.
5. Retest and stabilise
When the water is clear, bring free chlorine back to 1 to 1.5 ppm and pH to 7.2 to 7.4. Clean the filter once more. If the water is still murky after 72 hours, or the pool was green for weeks, call a professional: a drain and acid wash may be cheaper than weeks of chemicals.
Prevention costs less than the cure
One green-pool episode can cost 100 to 200 euros in chemicals, water and electricity, plus a week without swimming. Prevention is a weekly routine: test chlorine and pH, empty skimmer baskets, check the filter pressure and run the pump at least eight hours a day in season. Our guide to pool maintenance costs in Mallorca breaks down the numbers, and a professional weekly service typically costs 150 to 250 euros per month in season, less than two emergency rescues.
| Step | Action | Timing |
|---|---|---|
| 1. Test and correct the pH | Bring the pH to 7.2 so chlorine works at full strength | Hour 0 |
| 2. Shock chlorinate at dusk | 300 to 500 grams for a standard 8×4 pool | Evening of day 1 |
| 3. Run the filter non stop | 24 hours a day, backwash whenever pressure rises | Hours 0 to 48 |
| 4. Brush and vacuum | Walls, steps and corners where algae clings | Daily |
| 5. Retest and stabilise | Free chlorine 1 to 1.5 ppm, pH 7.2 to 7.4 | Hours 48 to 72 |
Why does my pool turn green in Mallorca?
Algae growth, almost always triggered by low chlorine combined with heat. Mallorca summers push water above 28 degrees, where unprotected water can turn green in 48 hours. Common causes: clogged filter, short pump cycles and pH above 7.6.
How fast can a green pool be fixed?
Usually 24 to 72 hours: correct the pH, shock chlorinate, run the filter continuously and brush the walls. Heavy neglect with sludge may require draining and a professional clean.
Can I swim in a green pool?
No. Green water can carry bacteria and micro-organisms that cause ear, eye and stomach infections, and poor visibility is a safety risk for children.
How do I stop it coming back?
Weekly chlorine and pH checks, 8+ hours of daily filtration in summer, and cleaning the filter monthly. A weekly professional service typically costs 150 to 250 euros per month in season.
Conclusion
A green pool in Mallorca is almost always low chlorine plus summer heat, and with the right 48 hour routine you can fix it yourself: correct the pH, shock at dusk, filter around the clock and brush daily. If the water is still murky after 72 hours, or you would rather hand the whole routine over, request free quotes from vetted builders and maintenance professionals.
This might be interesting to you
Buying a house with a pool in Mallorca: the inspection checklist
Paperwork, the 48 hour leak test, equipment age and running costs: the pre purchase pool checklist f...
Community pools in Mallorca: rules, costs and liability
Sanitary duties, annual costs and how the assembly decides: the guide for owner communities in Mallo...
Pool building permits in Mallorca: what you need to know
Do you need a licence to build a pool in Mallorca? A plain-English guide to permits, approvals and t...
Pool glossary for Mallorca owners: Spanish, English and German terms
Vaso, depuradora, final de obra: the Spanish pool terms every foreign owner meets, translated and ex...