I'm using the same stones (from wallyworld) and agree they don't seem to really "bubble" I'm thinking of trying a bubbler hose section with a fitting on the ends to allow a 1/4 hose connection for the air pump should allow more bubbles?! just an idea that I'm still trying to find parts for .. maybe that will give you an idea as well... whoever gets it working first let the other know ? i'm just on wk two of my first hydro grow as well.. I started 6 AK48s a wk ago friday will post pics on fri .good luck..