On 3/1/06, Olin Lathrop wrote: > > Dave Tweed wrote: > > Most fish tank pumps pump air, not water. Where'd you get that idea? Powerheads are very common, for undergravel filters (which were first done with bubbling air), and then there's the back of tank pumps which also do water only. The back of tank units have the electrical part isolated from the water, and the powerhead units are usually completely submersible. The vibrating bellows pumps are still around, but not a serious player. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist