What does no chlorine in the pool mean in practice?
The cause may be strong organic load, sun, incorrect pH, incorrect dosage or too long a break in care.
When does it matter?
Clear water without a measurable disinfectant is not the same as hygienically safe water.
Which solutions are related to it?
You need to check the pH, stabilizer and dosing installation, and then add chlorine according to the volume and product label.