Malwart has the 12in stones in the aquarium section. like 4 bucks. and their crappy pumps to drive.
For low budget its probably the best bet.

Otherwise I would try and find the soaker air hose and make your own (do it yourself.
Bubble wands, air curtains are all other options.
GoldenGoblin Reviewed by GoldenGoblin on . Quick Question on Airstones? Hey, I was wondering how important it is to have a good airstone with fine bubbles? Because I am modifying my system and I need to add 8 new airstones... and I would rather not spent $50 per airstone for the ones that produce fine micron bubbles. What is an acceptable micron level for growing plants hydroponically? If anyone has found good cheap ($20) airstones that work I would be forever grateful :stoned: Thank you all for your time. Rating: 5