You guys love to spend money, don't you? I clean my RDWC systems as follows; fill and flush with tap water twice, use a toilet brush to get any buildup, fill'er back up with fresh water, nutes and aerated compost tea. The secret is keeping your water temps at or below 65 F. I don't toss or even disassemble anything, not tubing, not pipes, and for Damn sure not airstones.
NO BLEACH!! EVER!! Straight up, the residues from bleach create some of the deadliest chemical compounds known to man, like dioxin. Seriously, do you drink your hot tub water?! I haven't cracked the cap open on my H2O2 in 6 months. Plants prefer a living medium, so give it to them.
So I bet you're already thinking wtf? Why don't I have the world's nastiest case of Pythium rot?! It's the beneficial bacteria; they will, given the appropriate environmental conditions, EAT all the pathogens, help out your roots and keep the water sparkling. Think of it as a probiotic treatment for your Hydro system, lol