My pool is green, what do I do? If that is the question in your head right now, start by slowing down. A green pool is fixable, and very few of the steps that matter in the first hour involve chemicals at all. What matters first is keeping people safe, then finding out whether the pump and filter are doing their job, then learning what the water test says.
This guide is written for Tucson homeowners. It covers the safe checks you can make, why pools here go green so quickly, the mistakes that make things worse, and the point where it is time to hand the job to a pool company. Tucson Pool Cleaning Pro does no pool work. It is a free referral line, and a call is handed to a Tucson-area pool business, locally owned and independent of the line, that inspects the pool and prices any work itself.
My pool is green: the first four things to do
1. Keep everyone away from the water
When the water is green you cannot see the floor. A small child who slips in would be out of sight almost at once. The CDC reports that drowning kills more children aged 1 through 4 than anything else, with home and other swimming pools the setting for most of them. Shut the pool gate, check that it latches, keep children and pets indoors and tell any guests to stay off the deck.
2. Check that water is moving
Look at the return jets: is water pushing out? Listen at the pump. If it is silent, check the timer or automation schedule, and check whether a GFCI outlet or breaker has tripped. You may reset it one time. A second trip suggests an electrical fault, so leave the power off and get help. If the pump hums but does not run, turn it off; the guide pool pump stopped working explains what that can mean.
3. Clear the baskets and read the gauge
With the pump off, tip out the skimmer and pump baskets. Then turn the pump back on and look at the pressure gauge on top of the filter. A reading well above where it normally sits after a cleaning usually means the filter is clogged and water is struggling to get through. Write the number down for the pool company.
4. Test the water
Use a home test kit or fresh strips and note pH, free chlorine and, if your kit shows it, stabilizer (cyanuric acid, which keeps sunlight from breaking chlorine down so fast). Very low chlorine is the usual finding. The numbers help whoever treats the pool, even if the reading looks confusing in cloudy water.
Why Tucson pools turn green so quickly
Algae spores reach every pool on the wind. They only take over when the chlorine runs out, and in Tucson that can happen fast. The National Weather Service puts Tucson's normal July high at about 100 degrees, with 68 days a year at 100 or above on average. Hot water under a strong sun uses chlorine up fast, and algae grows quickly once nothing is holding it back.
The pump stopped
A tripped breaker, a lost timer setting or a failed motor means no filtering and no chlorine spread around the pool. In summer, a few days is enough.
Chlorine burned off
The sun breaks chlorine down. Stabilizer slows that, which is why most outdoor pools here use it, but it cannot stop it, and an empty tablet feeder is easy to miss.
Stabilizer too low or too high
Too little and the sun strips chlorine within hours. Too much, from years of stabilized tablets, and the CDC notes chlorine works more slowly, so algae gets ahead.
A monsoon storm
The monsoon runs from June 15 to September 30. Rain, leaves and dust from a storm's outflow winds land in the water and use up sanitizer overnight.
Debris and phosphates
Leaves, pollen, bird droppings and some fertilizers add nutrients that feed algae. A pool with a lot of trees around it needs more attention.
Nobody was home
A summer away, a vacant rental or a missed service visit gives algae the weeks it needs to turn a pool dark.
What not to do with a green pool
Most of the damage to green pools comes from well-meaning shortcuts. These are the ones to avoid.
Do not combine pool chemicals
The CDC warns that pool chemicals should never be mixed with each other or with anything else, and that chlorine products combined with acid can release toxic gas. Never pour two products into the same bucket, and never use one container for different products.
Do not dump in whatever is in the shed
Pouring several products in at once, guessing at amounts, can push pH far out of range, cloud the water further, or raise stabilizer that then takes a drain to bring down. If you add anything, use one product, follow its label exactly and keep a note of what went in.
Do not drain it on a hot afternoon
Draining is not a quick fix and it has rules. The City of Tucson and Pima County want pool water sent to your own sewer cleanout where possible, after at least 72 hours without new chlorine and with pH between 7 and 8. A pool company can tell you whether draining is needed at all; read draining a pool in Tucson before anyone opens a valve.
Do not swim or let the kids in
Even a pale green pool can hide a child at the bottom of the deep end. Wait until the water is clear and tested.
Storing what you already have
While the pool waits for help, make sure the chemicals around it are safe. The CDC advises keeping pool chemicals in their original labeled containers, dry, locked away from children and pets, out of direct sunlight and below 95 degrees, with incompatible products stored apart. In a Tucson garage or side yard in summer, that last part takes some thought: a shaded, ventilated cabinet is better than an open shelf in the sun.
What the color and your checks are telling you
Use this table to decide whether you are looking at a quick recovery or a job for a pool company. It is a guide, not a diagnosis.
| What you find | What it often means | Sensible next step |
|---|---|---|
| Faint green tint, floor visible, pump running | Chlorine ran low for a short time | Test, correct with one product by the label, or ask your regular pool company |
| Cloudy green, floor hard to see | Algae through the water, filter loading up | Call a pool company; this usually takes more than one visit |
| Dark green or black, smell, debris on the floor | Weeks or months of neglect | A professional green pool cleanup |
| Pump silent, hums, or the breaker trips again | An equipment or electrical problem | Leave it off and call; the water cannot clear until it runs |
| Filter gauge far above normal | A clogged filter | Ask a pool company to clean or service the filter |
| Chlorine reads fine but the water stays green | High stabilizer, poor circulation or a bad test | A full water test by a pool company |
When to call a pool company
Call when any of these is true: you cannot see the floor, the pump will not run or keeps tripping the breaker, the filter pressure is high and stays high, you do not know what has been added to the water, or the house has been empty and the pool has been dark for a while. Call too if a neighbor's dark pool worries you; Pima County asks residents to report mosquito breeding problems, including green pools, to 520-724-7908.
When you speak with the company, give it what you found: the filter pressure, the test numbers, whether the pump runs, how long the pool has been green and anything that has been added. Ask what it thinks caused the problem and how many visits it expects. If repairs come up, request the company's Arizona Registrar of Contractors license number and enter it in the Registrar's online license lookup (opens in a new tab). Once the pool is clear, a regular routine keeps it that way; the Tucson pool maintenance schedule lays one out, and pool cleaning and weekly maintenance explains what a service visit covers.
Pool turned green? Call the free line any hour, say what you found at the pump and filter and which part of the Tucson area you are in, and you will be put through to a local pool company that can come look.
How the free line works
- Dial the line(520) 372-1083 is picked up by an automated assistant around the clock, holidays included.
- Say what the pool is doingGreen water, a pump that is silent or grinding, a light that will not come on, white crust on the tile, plus the part of the Tucson area you live in.
- Get transferredYour call is handed to a pool service company in the Tucson area that is independent and locally owned. It gets a quick summary of the problem before it says hello.
- Work it out with themThat company inspects, quotes, does the job and bills you itself. If nobody picks up, your name, number, area and pool problem go to the company so it can phone you back.
About this line: Tucson Pool Cleaning Pro is a free phone line, not a pool company. It answers your call and connects you with an independent local pool service company, which inspects, quotes and does the work, and which you pay directly. Companies may pay a referral fee. The line never charges you. Read how the line works.