Hi, I've never in 10 years had a problem with them. I guess it depends
on your pond, fish load,debris falling in pond etc. I know of numerous
people that use them successfully. I guess as with the lava rocks it
depends on the variables and conditions of your pond. That's the fun
thing about newsgroups and the exchange of ideas. You glean info from
them, from other peoples experiences. Try them, sometimes they may work
for you and sometimes they may not. I just use 3M pads and a thick mat
of water parsley and my pond is fine. Everyone's conditions are
different. {:O) Thank for the input and info!!
MIKE ++I don't know
what kind of lava rock you used,++

Grab your pig’s feet, bread, and gin,
there’s plenty in the kitchen.
I wonder what the poor people are eating
tonight?
Albert J."Fats" Waller