Advice / Live it
Turning a Green Pool Back to Blue: What It Actually Takes
6 min read · Published September 2026 · By Ultimate Pools
If you’ve walked out to your pool and found it looking more like a pond, don’t panic!. Green pools are one of the most common issues our team sees coming into spring. With the weather warming up, it doesn’t take long for your once blue pool to start turning green.
The good news: it’s fixable. The honest news: it’s not quick, and it’s not a $100 job. If you’re expecting someone to turn up, add a bit of chlorine, and hand your pool back to you looking swimmable that afternoon, this article will save you some frustration.
Why pools turn green
The “green” you see in your pool is actually algae growth. Algae takes hold when your circulation, filtration and chemical balance are outmatched by the current environment. It’s easy to forget about your pool in Winter – they are used less, maintained less and it doesn’t take much for things to start falling apart. Once algae gets a foothold, it multiplies fast, and the longer conditions favour it, the more of an issue it becomes.
Why it’s a process, not a single visit
A green pool isn’t corrected in one appointment. Recovering a green pool typically takes several visits over one to two weeks, sometimes longer depending on how far the algae has taken hold. Here’s roughly what’s involved:
- Testing and assessment. Water needs to be tested properly before anything else happens: your pH and chlorine levels are the two most important chemical factors in recovering a green pool.
- Shock treatment. To overcome the algae growth in the pool, we need to kill it off using a heavy dose of chlorine. To allow the chlorine to do its job better, we lower the pH at the same time to increase the sanitary effectiveness of it.
- Filtration and circulation. The pool pump needs to run continuously to clear dead algae from the water, and filters often need repeated cleaning or backwashing along the way as they clog with the debris being filtered out.
- Vacuuming and clean-up. Dead algae settles on the pool floor/steps and needs to be manually removed once the water has cleared enough to see it.
- Rebalancing. Once the water is clear and the pool is clean, chemical levels need to be retested and adjusted, to get the pool back to status quo.
Each of these steps takes time, and most green pools will require two, three, or sometimes four visits before the water is genuinely clear and safe to swim in again.
The process takes time
Bringing a green pool back to blue involves real time, labour, and a meaningful volume of chemicals, and that adds up. If a quote for a green pool recovery sounds a lot like the cost of a single routine service visit, it’s worth asking exactly what’s included. A full recovery costs more than ongoing pool care, which is exactly why regular maintenance through the quieter months is worth having in place. Our guide to swimming pool aftercare goes into why consistent care throughout the year is almost always cheaper than the alternative.
Can you do it yourself?
You can. It’s absolutely possible for a determined pool owner with the right equipment, chemicals and patience to recover a green pool. Realistically though, most people start the process, hit the second or third day, and decide it’s easier to hand it over. There’s no shame in that: it’s genuinely time-consuming, and getting the chemical balance wrong along the way can slow the whole process down further. If you’re weighing up whether to handle pool care yourself long-term or hand it to a professional team, our article on Pool Valet vs DIY breaks down what each option actually involves.
Or let our pool care team handle it
This is exactly the kind of job our pool care team deals with regularly. We bring the right chemicals and equipment, we know how many visits a given pool is likely to need once we’ve assessed it, and we do the hard work so you can sit back and watch the recovery process. What we call a “one-off” green pool treatment is often a series of visits to chip away at the pool, and we’ll always be upfront with you about that from the first assessment.
Frequently Asked Questions
How long does it take to fix a green pool?
Most green pools take one to two weeks to fully clear, spread across several visits. A pool that’s only just turned might clear faster; one that’s been sitting for longer will take more time.
Can I swim in my pool while it’s being treated?
No. The water isn’t safe to swim in until the algae has been killed off and the chemical levels are back in a stable, balanced range. Your pool care technician will let you know once it’s ready.
Will my pool filter be damaged by a green pool?
Not usually, but it will need extra attention. Filters clog quickly with dead algae during the recovery process and often need repeated cleaning or backwashing to keep the system running properly.
Why did my pool go green if I have a cover on it?
Covers are a good way to stop chemical loss through evaporation, but they also trap in heat. Whilst the extra warmth may be appreciated when it comes time to swim, those extra few degrees can increase the growth rate of any algae currently in your pool. Before you know it, that small patch of algae in the corner of the pool can develop it a full on algae bloom.
Is a green pool a sign something is broken?
Not always, it can simply be a result of a chemical imbalance and environmental factors. If you suspect that there may be an issue with your pool equipment, it’s best to get it checked out ASAP.
What’s the best way to prevent it happening again?
Regular pool care throughout the year is the best way to keep your pool looking blue. It’s often faster and cheaper to do regular maintenance every fortnight/month than it is to recover a green pool at the beginning of the season.
Related reading
- The Real Guide to Swimming Pool Aftercare
- Pool Valet vs DIY: How to Decide Who Looks After Your Auckland Pool
- Self Cleaning Pools: The Vantage System
If your pool has gone green, reach out and we’ll give you the honest rundown of what it’s going to take to fix.
