-- does fall short on calcium, I just switched from -- to coralife and so far am happy with the results, like already stated if you have some high calcium demanding corals you will need to boost the cal. in reef crystals. FYI I just did a water change with the coralife, and tested before adding to the tank, cal. was 450ppm, alk 2.6 to 2.8 mg/l, and mag. was 1360.