Pool care articles
Pool turned green between visits
A pool turns green because the disinfectant fell too low to hold back algae. Testing chlorine and pH and checking that the pump and filter ran shows why it fell. Keep swimmers out until the water tests right, not just until it looks clear, since cloudy water can be a warning that there are more germs in the water than normal. Call Sullivan's Pool Service right away with any recent test results so we can assess it and quote the recovery.
Tell us right away when the water changes
A green pool between visits can be unsettling, but the fastest path back to clear water starts with what you tell us. After every visit we leave a note describing what was done, what was added, and what to watch for in the days that follow. If the water starts to shift despite that routine, we would rather hear about it early than at the next scheduled stop.
When you reach out, mention any recent test results you have on hand. Those readings help us understand what changed and how far along the shift already is. In the meantime, keep swimmers out of the pool until the water tests right again, even if it still looks inviting on the surface.
Circumstances also change on their own over a season. If the water, the equipment, or the way the pool gets used shifts in some way, talk with us about whether the current level of care still fits.
Why the water turned
When a pool turns green, it means the water stopped holding enough disinfectant to keep algae in check. Algae were always in the water waiting for that opening. Once the level dropped far enough, they grew fast enough to see.
Figuring out why the level dropped takes a few steps. Testing the chlorine and the pH shows where the chemistry stood. Checking that the pump and filter actually ran shows whether the water was being circulated and cleaned the way it should have been. One of those checks usually points to the cause, and sometimes more than one was off at the same time.
Until the water tests right again, keep swimmers out of it. Green water is not just unattractive, it is a sign that the water is not being held in a condition meant for swimming. Once we assess the pool and quote the recovery, you will know what bringing it back involves.
Clear water is not the same as safe water
When a pool shifts from clear to murky, the instinct is to judge it by eye. That instinct can mislead you. Water that looks acceptable on the surface may still hold more germs than usual, which is why health authorities treat cloudy water as a warning sign rather than a cosmetic issue. One old lifeguard habit still holds up: if you cannot see the drain at the deep end from where you stand, stay out.
Appearance only tells part of the story, so testing matters. Federal guidance for residential pools calls for a free chlorine level of at least 1 ppm, rising to 2 ppm when cyanuric acid is in the water, along with a pH somewhere between 7.0 and 7.8. Until a test confirms those readings, the water should stay closed to swimmers.
Clear is a look. Safe is a measurement, and the test result is what settles it.
How recovery is assessed and quoted
Before any work starts, we want to know why the water turned in the first place. Once we have that answer, we put together a recovery quote and wait for your approval. Nothing begins until you have seen the estimate and agreed to it.
Recovery itself follows a set order. We test the water, including stabilizer, then clear out whatever debris is sitting in the pool. From there we correct the chemistry, get the filter doing its job, and retest until the water holds. The estimate reflects what that process actually requires for your pool, because it depends on the tested water, the condition of your equipment, and the amount of work involved.
One thing we will not do is promise a fixed number of days or point to a change in color as proof the pool is safe again.
Draining is not the automatic answer
When a pool has turned green, emptying it can seem like the obvious fix, but draining is only one option among several, and not always the right one. Sullivan's Pool Service looks at both treatment and water replacement for the specific pool before recommending anything, so the decision fits the situation rather than following a routine.
There is also a disposal rule that matters in Austin. Pool water may go to a storm drain only when it contains no algae, no chlorine or other pool chemicals, and has a pH between 6.0 and 10.5. Green water fails on more than one count, so it cannot simply be pumped out to the street.
Because these options are weighed before any draining work begins, a pool is not emptied when a full refill may not be possible. That assessment happens first, and the recommendation follows from it.
In Austin
Fill water matters here. Austin Water reported finished water leaving its three plants in the second quarter of 2026 at pH 9.65 to 9.74, total hardness of 76 to 77 mg/L as CaCO3, total alkalinity of 51 to 60 mg/L, and 2.52 to 2.69 mg/L of chloramines. Those are averages for tap water, not readings of your pool, so test the pool itself after a top-up.
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Sullivan’s Pool Service maintains pools in and around Austin, including Northwest Hills, South Austin, West Lake Hills, Tarrytown, Great Hills, River Place, Crestview, East Austin, North Austin, West Campus, Hyde Park, Downtown Austin and St. Johns, and in Bee Cave, Cedar Park, Georgetown, Leander, Pflugerville and Round Rock. See every service area.
Weekly residential service has one fixed monthly price, set by pool size: see pool service pricing for what each size tier covers.
Tell us about your pool
Tell us your service location and whether you need weekly care, help with equipment, or a one-time service. Call or send the quote form. We’ll confirm availability and the next step for your pool. Repairs and other separately quoted work are discussed before approval.