Hello all from SW Mississippi. I have been reading the forums and going through pool school and have learned ALOT. A little background. We got the pool with the house in Nov 2013 and have never had a pool before. We got pool stored last season with medium results, i.e. green water, clear water and then green back to clear. I started learning what chemicals did what being the nerd I am and tried to keep it the best I knew. Now to my question. We had a little trouble near the end of last season keeping the water clear. Shocking for several days didn't clean it up like it did at the beginning of the season. Talked to the pool store and got a bottle of filter magic. After using it the water started to clear on up and for a few weeks I could turn the pump off and on without backwashing. I noticed before that if I turned the pump off and then back on to clean the skimmer basket or pump basket that a greenish brownish cloud would come out of the return so I just backwashed and rinsed before turning it to filter. I have had clear water with some brown stuff (Algae?) in spots throughout the pool. It clouds when swept. After reading on here I have a two ideas. Deep clean the filter or just replace the sand. I'm not sure how long the sand has been run in the filter. I apologize for the long post. Thanks for y'alls help in advance.