phosban can be put into your filter in a small micro mesh bag, but it works way more effectively if it is in an area of high flow where all the surface area can be used.... hence using the reactor.
phosban and phosguard are different but achieve the same thing. phosban is ferric oxide (iron oxide) and phosguard is aluminium oxide. there have been lots of what i would call "anecdotal" evidence that aluminium oxides after time can leech into the water causing an aluminium toxicity. the general consensus on most boards is that ferric oxide is better than aluminium oxide. so, in light of that i'm going to recommend phosban or ROWAphos.
if anyone else wants to chime in, please do. this is one of those unsolved mysteries of reef chemistry and im sure there are other opinions. im also not a chemist but i did stay at a holiday inn last night, so take that for what its worth.
