Now launching on iPhone

Dip. Snap. Know what to add.

PoolLevels reads your test strip from a photo, works out the saturation index the way a water chemist would, and hands you one dose sized for your pool, with the arithmetic printed underneath. No colour wheel. No guessing. No trip to the store to be told what you already measured at home.

Coming to the App Store See how it works

Launch build is with Apple for review. Days away.

iPhone. No account. Your readings stay on your phone.

How it works

Three steps from a wet strip to a number you can pour.

Dip and shoot

Lay the strip on white paper in the shade and take the picture. The app finds the strip on its own and reads every pad. A 7-in-1 and a 4-pad strip are told apart from the photo, not from a setting.

Check the read

Each pad's colour sits beside the chart colour it matched, and any pad the app is unsure of is flagged so you can see which numbers to trust. Prefer your own numbers? Type them. The chemistry is identical either way.

Get the one thing to add

Corrosive, balanced or scaling, then a single dose sized for your gallons, the working shown, and the rule that keeps you out of trouble: half first, circulate, retest, then the rest.

The index, not a guess

Real carbonate chemistry

The saturation index from pH, total alkalinity, calcium hardness, cyanuric acid and water temperature, using the Plummer and Busenberg carbonate equilibria and Davies activity coefficients. Cyanuric acid is not quietly treated as zero: leaving it out moved a real sample by 0.18 and flipped its verdict from corrosive to balanced, so a missing reading suppresses the verdict instead.

One thing to add

A dose you can measure

Sized for your pool's actual gallons, rounded to a precision you can pour, with the arithmetic shown so you can check it. Always half first, circulate, retest, then the rest. It is easy to add more and very hard to take any out.

It stays on your phone

No account, no ads

There is no sign in, no advertising and no tracking across other apps. Your readings, your pool and your strip photos are stored on the device and nowhere else. The only thing the app sends us is anonymous usage counts, such as which screens get opened.

Straight from the app's own maths

This is what a result looks like.

Real inputs, run through the shipping code. The index, the verdict, the dose and the line of arithmetic are exactly what the app returned.

Worked example 20,000 gal · plaster · chlorine

pH7.8

Alkalinity110

Calcium388

Cyanuric46

Temp F84

+0.54 Scaling

Add 35 fl oz of muriatic acid.

That brings pH from 7.8 toward 7.5, and takes alkalinity about 7 ppm down with it.

26 fl oz per 10,000 gal per 10 ppm × (20,000 ÷ 10,000 = 2) × (6.7 ÷ 10 = 0.667) = 35 fl oz

Always add acid to water, never water to acid.

Dissolved solids are assumed at 1,000 ppm for a chlorine pool unless you enter the figure from a store printout, which can move this index by around 0.1. The app says which it used on screen.

What it costs

Free to use. Pro when you want the camera every week.

Free

No card, no account, no time limit

Type your readings and get the full chemistry, forever
Five strip scans to try the camera
Every dose with its arithmetic, and your whole history

PoolLevels Pro

$4.99 a month

or $41.99 a year, billed through the App Store

Unlimited strip scans
The same chemistry, the same privacy
Cancel any time in your Apple ID settings

What a photo can and cannot tell you

A strip read is a first look, not a lab result. The readings come from matching each pad to the printed colour chart, corrected where that kind of strip has been checked against store tests, and the app flags any pad it cannot place. A store printout or a drop kit is still the reference, and the app is at its most reliable when you type those numbers in.

From the founder

I built PoolLevels for my own pool. Every store test ended with a printout telling me what to add for numbers I already had in my hand, and every strip left me squinting at a colour chart in the sun. I wanted the chemistry done properly, the dose sized for my water, and the working on the screen so I could check it myself. That is the whole app.

Ben Mouton, Alstig, Inc.

Your next test is the last one you have to think about.

Coming to the App Store Tell me when it is live

Free to start. Pro is $4.99 a month or $41.99 a year.