At 1st the water smelled fishy and we are using peroxide in the system. After several attempts the water guy has the system cycling 3 times a day. The smell is gone but now it spits from time to time and sometimes it will spit out black looking water. Usually at that point I will find green particals in the aerators, some large and some tiny. I was told by Kenitico that after 5 years of use I need to change the mediate? in the system as it is used to remove the sulfar smell from these pellets and they have broken down and need replaced. Do you know if that stuff is green in color or have do you any idea what this green stuff could be. The black water could simply be very dark green as the toilets are starting to get a greenish stain. Very hard to clean. Any help would be great.