New here not sure why it happens. I use Holland secret from future harvest used this for about 6 years now. I grow in coco coir drain to waste hydro I guess it is called. I have a five gallon resivior with filtered tap water resivior stays clean and nice until I start using their carboblast third week or so into flower and I start getting white slim on airstone which eventually plugs up my pump. I water every hr a bit with a little bit of runoff. I do have a fair bit of experience and thought the carboblast may help.