poolcntrl
Sign in

poolcntrl

Cntrl your pool with confidence.

Try the calculatorDownload on theApp Store

See pricing

How poolcntrl works

Everything else got easier. Now your pool does too.

  1. A test strip held up against the pool waterTwo fingers hold a dipped test strip in front of the water, so its pads can be read against the pool.

    Test your water

    Snap your test strip (in beta), or type the numbers in.

  2. A phone photographing the poolA phone is held over the pool with the water framed on its screen, ready to take a photo.

    Snap your pool

    Photograph the water (in beta). poolcntrl names what it sees and what to check next.

  3. The phone showing a dose beside a chlorine jugA jug of liquid chlorine sits on the pool deck. Next to it, a phone shows the amount to add, highlighted.

    Follow your steps

    Exact amounts for your pool’s size, surface and the chemicals in your garage. Jugs and cups, not chemistry.

  4. A reminder on the phone between testsA phone on the deck shows a reminder card, with the sun and a cloud overhead.

    Let it watch

    Weather, trends and reminders between tests, so the next problem is one you saw coming.

Confidence, not chemistry.

Exact math for the numbers you enter

Same readings, same answer, every time. Where a dose comes from a formula, we show you the formula.

Yours, not generic

Sized to your pool’s volume and surface, and to the chemicals already in your garage.

AI reads, chemistry decides

AI reads your strip and looks at your water, both in beta. The chemistry engine decides every amount.

How accurate are we? →

See it work.

The real engine on a sample pool. Change any number and the plan changes with it.

Your pool

Plaster · Chlorine

Water test

Your plan

One thing today

Add 69 fl oz Liquid Chlorine

About half a gallon jug · 10% · no extra pacing needed

Pour slowly with the pump running, near a return jet, and let it circulate. Best added at dusk — your stabilizer protects chlorine from sunlight, but adding it after the sun is off the water still gives it the whole night to work. Nothing about this amount needs extra pacing. Add it as the steps above describe, and let the pump circulate before you retest.

SWIM
When to swim
Safe to swim after 4 hours. Retest first.
4 h
after adding
RETEST
Why retest
Retest in 4 hours. Retest before applying any additional chemicals.
4 h
confirms it worked

Chemical to water, never water to chemical. Never mix with acid (produces toxic chlorine gas) or any other chlorine product.

Don't just watch the clock — retest before swimming. Water is safe when free chlorine is between 3 and 7 ppm, pH is 7.2–7.8, and you can see the bottom.

That dose is real — the same deterministic engine the app runs, same answer every time.

And when the numbers cannot be right — total chlorine under free chlorine, a pH no pool has — poolcntrl says so instead of dosing. Nothing gets rounded into an amount.

Pro already knows your pool, so you skip every field above — and checks your next test against the chlorine you add.

Engine ruleset mvp-seed-v1.43.0 · How this dose was worked out

Pro knows your pool.

Skip the typingPhotograph the strip. AI reads the pads into your test.
Name the problemPhotograph the water. Get a likely cause and what to check next.
Your pool, savedVolume, surface and sanitizer, saved once. Every dose is sized to your pool.
Know if it workedLog the chlorine you added. Your next test is checked against it.
Weather, before it hitsHeat, rain and storms show up as advice before they show up in your water.
See it comingA chart for every reading, so a drift shows before a problem does.
Told when to retestOn your pool’s own cadence, plus weather and filter notices.
Every test keptEvery test, dose and note kept, with what happened next.
More than one poolEvery pool and property you look after, in one account.

After your free two weeks, Pro is $5.99 a month or $49.99 a year.

The alternative is free, and it is a fair one — your pool store will read a sample on Saturday. Why pay for this instead →

Download on theApp StoreTry the calculatorSee what Pro includes →

Quick start guide

6 short guides, in the order you will need them.

  1. 1TestHow a water test works
  2. 2Read the numbersWhat each measurement means
  3. 3AddHow to add chemicals
  4. 4WaitHow long to run the pump after you add something
  5. 5RetestAfter you add chemicals
  6. 6Keep everyone safeKids, pets and pool chemicals

Closing for winter? The moment you mark the pool closed the reminders stop. When the forecast warms up in spring, poolcntrl asks whether you are ready to reopen.

Explore all guides →Where our numbers come from →Closing or opening your pool →

Ready for your free trial?

Your two weeks start the moment you create the account — no credit card. After the trial it’s $49.99 a year, or the free calculator forever.

You use the trial in the iPhone app — create the account with your iPhone in reach. This site is the read-only view of your pool.

How the trial and billing work

Your 2-week free trial needs no card and starts the moment you create your poolcntrl account, on the web or in the app — and you use it in the iPhone app. Subscribing afterwards happens inside the iPhone app through your App Store account. An App Store subscription also starts with two weeks free, if your Apple ID hasn't used this offer before. After that, it renews and charges until you cancel it, any time, in Settings.

By creating an account you agree to our Terms and Privacy Policy. No spam — only product updates.

Download poolcntrl now

Take your pool’s perfect routine with you. Free to start on iPhone — Android is on the way.

Download on theApp Store
On Android?The full chemistry engine runs free in your browser — the same server-side math the iPhone app asks for, and the same answer. No app to install, no account needed.Open the free calculator →

One subscription, every device — phone at the pool, laptop at the kitchen table.