WHAT SHOULD I DO WHEN THE WATER IS GREEN?
That green is algae 9 times out of ten. Otherwise, it's copper.
Check the total alkalinity level. It has to be between 125 & 150 ppm. Check the Ph, it has to be between 7.4 & 7.6
Adjust these 2 first.
The next day, add a shock treatment: concentrated algicide (at least 40%) and shock. Quantities depend on the quantity of water, how green it is, etc.
If you decide to have the water tested, bring in the list of the products you already have (and quantities) so you only get what you need.
The water will turn white, then the filter will clear it up. You can always add a clarifier to speed up the process.
WHAT SHOULD I DO WHEN THE WATER IS WHITE?
Is it after adding some granular chlorine (calcium hypochlorite)?
If it is after adding calcium hypochlorite, that white stuff is the calcium. It will eventually clear up, but that is a good sign that there is already more calcium than needed in the water. Change to trichloro chlorine. To clear up the water, use a skimmer sock in the skimmer basket as well as on the return, together with a clarifier.
IS IT AFTER ADDING ANY OTHER CHEMICAL?
If it's after adding any other chemical, it should clear up in 24 hours or so.
IS IT AFTER MANY BATHERS ENVOYED THE POOL FOR SEVERAL HOURS?
If it's because of lots of bathers, oxydize.
If it's after a shock treatment, make sure that the pump is on low speed, use a clarifier and skimmer sock in the basket.
Water analysis is always a good idea.