In finalizing the designs for the saltwater mixing station, I'm reconsidering the use of a Kalk reactor.
Years back I read a great article written by Randy Holmes-Farley on the benefits of adding vinegar to fortify Kalk. Since then, I've had success adding vinegar to Kalk, both to increase the amount of available calcium and as an added carbon source. I attribute this process (in addition to the use of DSBs) to my never having any nitrate issues. As this will be my first large tank with a SSB, I want to do all I can to maximize biological filtration - including the use of vinegar. The use of a Kalk reactor makes that more complicated. Instead, I plan on adding a covered 40 gallon brute to the mixing/storage station which will be fed by the RO/DI storage tank and hold an over-saturation of Kalk to which Vinegar can be dosed. This will be the ATO source.
This will allow me to continue using Vinegar, eliminate the cost of another reactor and most importantly - save space in the cabinet. It will also forestall the need for a larger CaRx and likely remove entirely the need for a bio-pellet reactor (Anecdotally, I found no benefits when I tested adding Bio-Pellets concurrently with vinegar dosing.)
Adding yet another water container will be a tight fit in the basement, but I think the benefits outweigh the inconvenience, and if for some reason it fails to perform as expected, I can always add the Kalk Reactor.