Green and cloudy at the same time usually means algae plus an overwhelmed sanitiser. Here is the step-by-step fix, from shock dose to safe to soak.
Short answer: water that is green and cloudy at the same time almost always means algae has started to grow and your sanitiser has been overwhelmed. The fix is a strong shock dose, a day of filtering, and a clarifier to polish out the haze. Do not get in until a test strip shows your sanitiser back in range.
Green on its own can be algae or dissolved metals from a fresh fill. Cloudy on its own is usually fine particles the filter cannot catch. When you see both at once, the most likely story is this: the sanitiser level dropped for a few days, algae began to grow, and the water filled with both living growth and the debris it produces.
Check your last week honestly. A busy weekend of soaks, a forgotten dosing day or a filter that has not been rinsed in a month is normally all it takes, especially in warm weather.
First, rinse or replace the filter. A dirty filter cannot clear a green tub and will simply put debris back into the water.
Second, check pH with a test strip and bring it to between 7.2 and 7.6 if it is out. Shock works far better at the right pH.
Third, add a strong chlorine shock dose with the jets running and the cover off. Follow the dose on the label for a shock treatment rather than a routine top-up. Leave the jets running for at least an hour.
Fourth, filter continuously for 24 hours. The green should fade to a dull grey cloud as the algae dies. Rinse the filter again at this point, because it will have caught a lot of the debris.
Fifth, add a clarifier. The dead algae is now a haze of particles too fine for the filter, and a clarifier binds them into clumps the filter can catch. Expect clear water within a day or two of the clarifier going in.
If the water has been green for more than a week, if you cannot see the seats, or if the tub smells earthy even after shocking, a drain and refill is quicker and cheaper than fighting it. Use a plumbing flush before you drain so the pipework does not reseed the fresh fill.
Treat it as unsafe to use. Algae itself is mostly a nuisance, but water with no working sanitiser can carry bacteria you cannot see. Stay out until the water is clear and a test strip shows sanitiser back in range.
Typically two to three days from the first shock dose. The rule is simple: clear water, sanitiser in range on a test strip, and no strong chemical smell.
Algae rarely appears from nothing overnight. It was usually growing quietly for days and reached visible levels quickly once the sanitiser ran out, often helped by warm weather and a covered, dark tub.