wood air stone skimmers

[rayjay]

I use the pondmaster linear compressor and they are extremely quite.
For my air stones, I use a pair for each skimmer and change them every 4 or 5 weeks, cleaning the removed one and drying it out and using it at the next change.
Two stones get me more than a year service.
The advantage of boring the centre hole is that you don't have to glue an assembly together.