Cool thread to read.
In realty, fitration is filtration, no matter if it's a big sponge like thing, a sump, 9 canisters chained together, whatever as long as the BB have a place to grow.
Very true. there are TB breeders that use only sponge filters as filtration.
the flourite is a non active substrate correct? meaning it won't dissolve or leach back out things?
could crushed lava rock (like GLA sells) be used a similar/cheaper substitute?