Caribsea aragonite buffers to the highest ph 82 making it perfect for african rift lake cichlids amp reef tanksr 125 195 mm diameter grain size a revolution in reef keeping this is the one youve been reading about in all the hobbyist publications this grade of aragonite is specifically engineered for plenum type nitrate reducing beds or anywhere a deeper bed is called forr the pore water space created by precision grading also allows maximum ph support and dissolution of calcium c