A FEW IMPORTANT DETAILS for anyone wanting to do this type of diffuser design:

1. You do NOT want to glue the two PVC caps on the tube. I just put them on really tight and put a small holder screw in. This way once a year I can pull it up, clean it out, remove any algae buildup, etc. Then you can put it back together.

2. On the bottom (the weight side), you will want to drill one or two small holes, just a HINT larger than the air holes. This allows the water to escape from the bottom when the pressure comes on after being off a while. That way you don't end up with a nasty water pool in the bottom.

3. My first pass I drilled WAAAAaaaaayyyyyy too many holes. That is why you see the black electrical tape on it. You only need a small band about 1/4" - 1/2" wide, with just a few small holes in it. I probably still have too many holes now.

4. Make the holes as close to the bottom of the tube as possible. This allows air to stay up in the top of the tube so that it floats off the bottom.

5. I used 3" PVC. If I do another one I would probably use 2" instead of the 3" pipe.

I used a very small, 1/16" drill bit for the air holes. However I used a 3/32" bit for a small relief hole on the bottom where the weight is. That allows any water that gets in to completely evacuate.

Just some design issues to consider if you were to try to do this type of a DIY diffuser.

Overall it seems to be working well and has pretty much a HUGE amount of flexibility in how much pressure I can run through it.

Last edited by woodb01; 08/16/13 12:04 PM.