Never had any mold using an aero setup.In my bigger 28-32 plant setup I use and posted in the aero section last month how to build ( pics of that 1 in my gallery also I found a little algae forming on the last 3 inches of the drain lines but I ran some industrial grade peroxide through it and its all gone.You could do the same in this unit as a preventative and it also increases root mass from the added o2 in the water.Its different then regular peroxide for cuts but is easy to get I got mine at local hydro shop for about 12 bucks a gallon.Glad this is helping some people out.The nutes I run Fox Farm and just follow the feeding schedule the company gives and maybe adjust up as you get used to it and what the plants like.I basically start my ppm around 850-1000 and end up at 1500-1800 ppm at finish.