Well, an interesting question Travis ... and discussion.
I guess I'd fall in the `don't consider it mandatory for all, but interested to try it' camp. No reactor here, just a low flow area of my sump has a bag of Phosban right now.
As I know how things are without running it [pretty good, actually] ... I figured it was worth a try. Like anything I felt I needed a good baseline before starting it, now in week 3 of running a test of it.
To keep in mind with some of the media chamber things is that they're almost designed with tank-size in mind IMO. The TLF one is made to run a can of Phosban, enough for 150 gallons. So on my 58g SPS tank, while I guess I could just load it up every six months or something ... I'm going low-tech for the minute. Might even DIY a chamber, seems like a simple enough task.
I dunno. I kind of feel that something's out of whack if you need to run this 24/7/365 ... it's easy to import and stock too heavily and all. It scares me that this will become something overhyped, or helpful in facilitating `insta-tanks' that seem to pop up here and there.
Heck, I'd love to have some fish I can't support the waste from ... and this would facilitate things
Although I'd just rather see if it makes my SPS frags become a `jungle' just a little quicker.
Without getting a real balance in the tank prior to using one of these ... it just seems like a nutrient band-aid like a DSB would be. Masking the problem.
Where while I see their use, it ain't no substitue for nutrient-balance and getting import/export in agreement.