If you are using liquid buffers and want to try corals/seashells my
recommendation is to add slowly and in a manner that you can remove
some/all if you add too much. For me, it only took a few tablespoons.
(it is hard to buy a few tablespoons of crushed coral, so now I might
as well do a marine tank with the extra right?)


Ditto me on the crushed coral. I started using a bag in the back of
the AC 300 filter. Now I dump a handful in the tank and it's
mixed/laying on the gravel. In my old house, my KH was only about 1-2
deg KH. Now I've brought it up to between 3.5 and 5 deg. Neat thing
about crushed coral, as I understand it, the more CO2 you add, the more
it will disolve the shells and the more buffer you have. So with
shells I think the odds are slim of a pH crash. I haven't seen
anything like one yet.

steve