I'm actually wondering more who
doesn't use GFO. For those who don't know, GFO is granular ferric oxide used to absorb phosphates. Brand names such as RowaPhos, PuraPhos, PhosBan, etc. I'm referring only to the RUST RED stuff, not the white stuff.
Multiple choice if needed...somehow.
Dangit, I screwed up...meant to have the YES options asking how you run it, REACTOR, in a FILTER (like an HOB power filter), or PASSIVELY (in a bag in the sump say). Please comment.
I run mine 24/7 in a reactor.