In this instructable you will be making your own Air Stone for oxygenating liquids. I use them for Aerated Compost Tea because the Blue Cylinders you get from the aquarium stores get gummed up and stop working efficiently over time.

This instructable assumes a working knowledge of power tools and general safety practices.

Step 1: DIY Air Stone/Bubble Stone

Collect your materials!

You will need....

1) Aquarium pump - Mine is a Tetra Whisper 20.

2) Air Hose (duh!) with a corresponding...

3) Drill bit - My drill bits are pretty much only good for wood and plastic. You don't need anything fancy.

4) Crappy drill - nothing fancy here.

5) Red Lava Rock - I think this bag was about ten bucks. I grab one with lots of big chunks.

6) Safety Glasses, Hard Hat, and anything else you might need to eliminate my liability and keep yourself safe.

Step 2: Drill It Out, Plug It In!

Red Lava Rock is excellent because its very brittle. So brittle that I just hold the stone in my hand while I drill it at nearly the lowest speed the drill is capable of producing. The bit doesn't really drill so much as scratch a hole in the rock. All the same, be careful!

I like to choose a bit that is a little smaller that my airline. This allows for some wiggle room at the entrance of the hole so that the air line can be wedged in and stay put without using adhesives or silicone or any of that. As you can see, the stone is stuck on the line good enough that it will support the weight of a larger (and soaking wet) stone.

I use silicone air line for this, its extra rubberiness provides a little extra tooth for the rock to bite into and stay put.