Hofer Gurgle Buster

[Delphinus]

I've built a couple, I had one on my old 72gal bowfront and the 20g tank I put together out of spare parts/surplus I had lying around, also has one of those. It's basically exactly the same idea as a Durso but takes up less space so can fit inside a tighter overflow.

In general I find Dursos and these to be a bit hard to tune with the airflow valve, but it's probably more a function of my workmanship than the design itself. Instead of drilling holes in the pipe I just Dremeled out some large chunks and I think basically there's just too much flow capacity through the holes. So I compensated for it by putting a valve on the drainpipe just to put a little backpressure on it.

Overall I think these Hoffmans whatever they're called aren't too bad. Basically a smaller footprint Durso. Quieter than just a drain pipe but you do still get a faint gurgling sound.

My 20g is empty (actually I'd be running the tank if I could, except that I don't have enough electrical circuits downstairs yet so I can't actually set it up for real just yet) but we could fill it with tap water and do a dry run.. er .. wet run for a demo if you wanted.