What calcium reactor ?

[reeferfulton]

Ok folks .
I am trying to decide what calcium reactor i should be buying .I need your help .
tank will be a moderately stocked SPS 140 gallon.
space is not an issue .

I would like to keep the cost of the reactor at 400 or below.
I have already budgeted 300 for the bottle reg package etc .

Seems to be tons of options out there , but I am having trouble finding any reviews etc .
I would like to buy one that is proven and been around for a while i suppose . Do not want to be a guinea pig or anything

thanks all