Wouldn't it be easier just to put a sponge around the bubbler? Then you would also have a feeding station for shrimp, fry and anything else that would eat the microorganisms.
not sure what you mean...wrap a sponge around the airstone, or the south end of the PVC? I can't see how the former would accomplish much. the latter is fine, if you have sponges sitting around that conform to that use. I don't care for sponges because they are trying to be both a mechanical filter and a biofilter at the same time, and the better they are at mechanical filtration (sucking junk in), the worse they are as biofilters (because now they are plugged up). with the jar filter, the floss acts just as a mechanical prefilter, keeping gunk off the biomedia so it always has good flow. the floss is easily changed without disturbing the biomedia, and it provides as nice a grazing area as the sponge, in my experience. but I would love to hear more about how you use the sponge; if there is a simpler way, my ears are open!
I use the bubbler filter your talking about (I think).
yep, that's the one!
When I was in Albany NY there was an old school LFS called Davey Jones Locker who used these as their only filtration in every tank and they were all clear and healthy.
there was a time not so long ago that those filters were about all that anyone used. you can't stock quite as densely as with the more efficient pump-driven filters we have today, but they do work great and are far less likely to have any sort of mechanical problems. I have in my collection one of the 1st transitional filters--a side-hanging box filter with air-driven flow! i'll have to take/post a pic of that one, it's a classic.
I throw in some gravel and filter floss and thats it. I guess I should use some bio media and it would be a lot better.
gravel is a great biomedium. there are more expensive media out there claiming massive surface areas, but I really have to wonder how many of those microscopic nooks and crannies actually receive water flow when the media are colonized/covered by a bacterial biofilm. would love to see some real world data on that. gravel worked for my dad, and his dad, ...