"Dave S" wrote in message
...
My LFS store has told me that I should change Eheim EhifiMech and
EhfiSubstrat every 8 months. When I asked the reason. I was told that
after a while 'bad' bacteria builds up and it becomes ineffective. If this
is the case, could I boil it (and thereby remove any impurities) and use
it again?

TIA - Dave

--
cadasco at hotmail dot com
Hampshire - UK
Thanks to all who replied. The info (as usual) is most useful. - Dave