Don't have an airstone...air pump to drip ring....I'm sure its the hydroton because it's the only thing different. Are you going to try the coco? I've heard about some weird issues with it and so was afraid of it. Also did not want to go timed watering the way you should with coco I'm told.....for me it just seems like one extra thing that could go wrong, lol.

Sharing do you use ro water?