If you have a regular-sized reef tank, an affordable 2-part solution such as BRS Bulk Pharma should be enough. You will not need to invest in a calcium reactor. Contrarily, a calcium reactor will serve you right if you are in either of the following circumstances. - You own a gigantic or high-consumption aquarium. - You use a high-end, costly 2-part solution. - You are okay with the long payback horizons. Finally, if you are into gears and gadgets with the affordability to have a reactor, then go for it, by all means. It will be well worth your investment. It is never a waste to spend money on the stuff you love and enjoy.