On Sep 6, 10:28 pm, "Pete C." wrote:
.....
The Harbor Freight #95563 is a rather nice 2.5l tank unit with heat and
when it's on sale / with coupon for about $60 it's hard to beat. It
passes the "blow holes in aluminum foil" test well so it has a
reasonable amount of power.

Pete C.

What's the "blow holes in aluminum foil" test? I've got two old L&R
ultrasonics that don't seem to clean well anymore; it would be nice to
have a quick generic test to put to them.

Thanks!
Dave