Red sea reef foundation abc is a complete powerder supplement containing a balanced powder mix of reef foundation a calcium strontium reef foundation b buffer reef foundation c magnesiumrobust coral skeletons are essential for all reefs and only acheivable by ensuring the basic elements calcium magnesium strontium and carbonate are readily available and in the correct ratio to each otherif they are not in the correct ration the coral skeleton can form as a fragile calcitecan also