first scrub all clinging algae from the sides and bottom of the pool with a pool brush then use a combination of yellow clear and chlorine shock to treat the water.
after 24 hours test the water for proper PH and free chlorine concentration, if the balance is off add acid or base and re-chlorinate.
most pool and spa stores will test your water sample for free and recommend the proper chemicals to achieve the correct balance.
shock the pool weekly and test the water for correct PH and free chlorine level.
properly cared for a pool will stay sparkling clear all year round and the treatments will run you less than $20 a month to maintain.
Answer
Have a professional pool company come in and give you an estimate. Check your sand filter and make sure it is not in need of replacement, or any other equipment fault. You may need to empty the pool and completely wash it down for algae and mold. You need to keep up the chemicals and cleaning practices and run the pumps during the winter if you don't want this to happen.
You have to treat pool water with pool chemicals and use a pool filter to get and keep the water clear.
Just the same as not putting enough chlorine in the pool. You can treat the water the same as you would have and increase the production of the salt system.
Green
The pool turned green in Rio due to an imbalance in the pool's chemicals, specifically the pH levels, which caused algae to grow and give the water a green tint.
The color of the pool is no problem at all. If the water is green, who in his right mind would jump in?
It is not the salt water pool or the salt water that is turning your hair green. It is a poorly maintained pool with a chemical imbalance - pH and total alkalinity out of required parameters.
I am not sure why this has not been answered. The most common reason for the green is algae growth. If you put on a solar cover and ignore pool maintenance, then the algae will grow as the water heats and when you remove the cover, the pool will be green
You must first determine the cause of the green water - then rectify that. The green water could be the result of the equipment not functioning correctly, or not being operated correctly, or being undersized for your pool. Or it could be a water balance problem.
Shock it. Sold at Walmart, Lowes, or possibly your grocery store.
Green pool water is caused by algae. To remove the algae, bring the pH level of the water to 7.8, scrub the sides and bottom of the pool, shock the water with chlorine, then vacuum up all the dead algae.
If you are not worried about the pool floating on a high water table or you have a hydrostatic valve on the bottom. I would drain it clean it and start again.
The pool water is green because of algae- which is a type of plant. You just need to add more chlorine to kill off the algae...