12.6 dkh / 465ppm calcium

According to red sea, they suggest 12.6 dkh and 465 ppm calcium for 'SPS / Clam rapid growth'

I have a friend whos opinion I respect telling me that this is grossly inaccurate for a number of reasons.

Red seas charts can be found at: http://www.redseafish.com/uploadima...on/Manual Foundation Complete GB 24023_4w.pdf page 3.

They do not state any ill effects of keeping alk/ca levels this high, nor do they imply this will cause any damage to livestock or corals.

RHF's calculator seems to state that this is pretty close to being a balanced ratio, and is only slightly outside his happy zone according to http://reef.diesyst.com/flashcalc/flashcalc.html



Premium Member
Those levels should be safe enough. You might see a bit more growth than at lower levels, but I doubt you'd notice any difference. The corals could be light or food-limited, for that matter.