"Duncan A. McRae" wrote in
.rogers.com:

What about poo? Ammonia/Nitrite/Nitrate aside, what breaks down and
devours the sludge component?

Plant roots will eat that.

Planted tanks do need water changes though, for many reasons. A big one is
micronutrients that don't enter the tank in any other way. Another is the
fact that evaporation will take H2O away, but not dissolved metals,
calcium, etc.

Water changes are vital to healthy tanks IMO and IME.

~Empty

--
'You're not friends. You'll never be friends. You'll be in love till it
kills you both. You'll fight, and you'll shag, and you'll hate each other
till it makes you quiver, but you'll never be friends. Love isn't brains,
children, it's blood... blood screaming inside you to work its will. I may
be love's bitch, but at least I'm man enough to admit it.'
Spike