The buffer recipe is a choice, here in HB the water we have huge problems with in regards to keeping africans really, we have a Ph of 7.5-7.8 and the KH is 3 or lower :-? We have found no amount of coral in the filter, or substrate buffers the water naturally enough and these are in huge Aquis 2400 canisters which huge water flow. This could be the case in other places too around NZ. If you know what you are doing with the buffers, then they are sweet to use. We run coral rubble in the external canisters, lime stone rocks, coral sand or marble chip and this does nothing in naturally buffering the water here.... so next step... buffer recipe, the fish love me for it 8)