What kind of airstone have you tried using? The blue ones will not work. If you can find a Limestone wood airstone, these work fairly well. I had one when I used DIY C02, and the pores are so small the bubbles are about as big as with a glass diffuser. The bubbles also got much smaller from their exit to the surface, which means they were definately dissolving into the water. At most places the limewood airstones are about $3 for a 2-pack. Try it out and see what you think