"JamesG" wrote in message
oups.com...
Mike,
I am not familiar with cotton batting, but if it is made with cotton
then it would rot out quickly. I tried lava rocks also but they clog
up more than pot scrubbers and are heavier. The surface area for
bacteria is quickly used up and clogged.

James


I suspect the previous poster meant polyester batting. You can buy it from
fish stores, but it's much cheaper if you buy the same stuff from a fabric
store. It's sold as pillow and quilt insulation material.

-S