So my aquarium is up and running and I have been interested in getting a calcium reactor before I begin to add any SPS Corals to my system. So I don't normally concentrate too much on price when purchasing equipment. But this thought just came into my mind and I can't seem to shake it to justify the price. Calcium Reactor A has a size specification of L: 7 1/8" x W: 5 1/2" x H: 19 3/4" and is rated for 120 gallons of water. Calcium Reactor B has a size specification of L: 8 1/2" W: 6" H: 19 3/4" and is rated for 290 gallons of water. So the both use the same pump design and the only difference is the size. So my thinking is such. The difference in size is L: 1 3/8" x W: 1 1/2" x H: None. So does having that little but more media really mean anything? I mean the reactor is going to release only as much calcium rich media as we configure it for. Then only problem I see would be that I would have to change the media more often. So is convenience really worth an additional $600 more? Let me know if my conclusion seems totally wrong.