They're all looking sound the one in the oxypot has proper took off. I haven't had to change Ph once or clean its roots. The two in bb are looking fine and healthy not as big as oxypot but just as healthy I've gt my room temp at 23 and both oxypot and bb temps are at 19. My nxt rez change is tomorrow so wat would the mill per liter be for 15 ltr oxypot and 50 litre bb. I'm off to hydro shop to see if they've gt the air pump u said and the stones and more rhizatonic shud I gt 1 liter or 500 mil. And ill gt more cannazym to. The hydro guy says they might have that pump or somethin similar. I will only gt the one u said as the ones I have are far from being silent.