Free diagnosis: what's wrong with your water?
Answer a few questions about what you see and you'll get a first diagnosis, with the matching guide. For the full diagnosis with real numbers, you'll need to test the water — the app takes care of that.
What colour is your water?
And on the surface?
Any smell?
Any discomfort while swimming?
That looks like algae
Green water = algae 9 times out of 10, usually after heat, a drifting pH or not enough sanitiser. Good news: it's fixable, and faster than you'd think.
Read the guide : Green pool water: causes and step-by-step treatment
Probably metals (iron, manganese)
Brown or rust-coloured water, especially after a refill or well water: metals have oxidised. Whatever you do, don't shock it with chlorine before reading the guide.
Read the guide : Brown or rusty pool water: metals, and the chlorine trap
Milky water: chemistry or filtration
Milky white water comes from an imbalance (pH, alkalinity, limescale) or filtration that can't keep up. The guide helps you tell them apart.
Read the guide : Milky or white pool water: causes and fixes
Cloudy water: several suspects
Not enough filtration, unbalanced chemistry or early-stage algae. A water test settles it in 30 seconds.
Read the guide : Cloudy pool water: the 3 causes and how to clear it
Foam: your water is "worn out"
Sunscreen, cosmetics, residues… The water has built up too much organic matter. It treats well.
Read the guide : Foamy pool or hot tub water: why, and what to do
Chlorine smell = chloramines
Counter-intuitive but true: a strong chlorine smell means there's NOT ENOUGH active chlorine. It's the chloramines you can smell.
Read the guide : Pool smells strongly of chlorine: it's actually running low
Stinging eyes: pH or chloramines
It's almost never "too much chlorine": it's a drifting pH or chloramines. A test confirms it in 30 seconds.
Read the guide : Stinging eyes at the pool: it's (almost) never too much chlorine
Nothing alarming to the naked eye 👍
The eye can't see everything: a drifting pH or fading chlorine is invisible. A quick photo test with the app and you'll know for sure.