calcium reactor questions

[Lampshade]

They seem to be an odd ball item, hard to find, i got it off a shutdown on craigslist. I recently replaced the impeller and ended up having to go to tunze to get it. I have lots of room under my tank, I'd be up for a trade if you end up finding an external that's comparable. Just an option, this is working fine for me now, but if you decide you want it and can't find one let me know.