I have awful dirty dark green water even after days of shocking. I too am beginning to think I need to change sand. I usually can just shock and get past this, but it doesn't seem to be working. In addition, for the past few years there has been a small amount of sand in my polaris bag every time I use it, I would assume this adds up over time. I also don't seem to need much of a backflush when I do so, seems like I used to get gunk out for several minutes and now hardly anything. Could all this point to need for sand? Is this a special item or just regular old sand? The stuff in my polaris seems fine and white. Also, should I remove old sand or just add on to what is there? THANKS IN ADVANCE!!
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