I have filled my water holding tank three times this year. So you can see I don't use it alot. I have checked and cleaned the filter each time I fill the holding tank. Just yesterday I was at my boat doing some cleaning, and noticed something in the water. Looked like some brown particles. I feel I need to put something in my fresh water holding tank to rid it of this kind of sediment or what ever it is. Can anyone advise as to what type of additive. I know chlorine works well in my pool, but not sure for a holding tank. Thanks, for any advise.