I am looking after a pool for the first time this winter and I am going to be absent (abroad) most of the winter so would like to winterize it. However the pool has gone green and I have half drained it so it is half full, and put lots of chlorine in it. I have left it now with the filters off (as the water is below filter level anyway). I am worried that the algae will stain the grout between the tiles of the pool, does anyone know if this will happen if I just leave it green? Also is it ok to leave it half full and is there any way in which I can get it clear again within 4 days as this is the max time I will be available to try and cure the algae before being away working again!

Welcome to TFP!

You have a lot of things working against you. It's going to be virtually impossible to do much without the pump in operation, and no matter what you do the water will be green again without regular care while you are gone.

Where is the pool located? Weather makes a big difference in what you need to do. You almost certainly need to get more water in the pool to protect it from ground water damage.

Post some more information, and we can try to advise you.

The good news is that algae stains can typically be removed with high chlorine levels.