I think its time for a major cleaning of my system. This is the first time I've had this much mold growing on my cubes? Plants were fine the entire grow but these cubes look like they've been through hell. Anyone ever had this happen before?
Typical cleaning after a grow consists of tray and res scrub (warm water only), rinse and clean pump, then run system in Hydrogen peroxide solution for a couple of hours. Maybe I was too light on the peroxide?