buffer pH

["Roxanne Bittman" <rbittman at dfg_ca.gov>]

I would use Equilibrium (Seachem) or R/O Right instead of lime or just
calcium carbonate to buffer the water.  Plants need more than Ca and
carbonate to make leaves!  Pure R/O water has nothing in it at all, so
you either have to add Mg, Ca, etc or better yet, add back a little tap
water to do the same thing.  That's what I do, though I have found that
Onyx substrate (which I use) has quite a strong buffering capacity and
has both Mg and Ca in it already, so I seldom have to add tap anymore.
Roxanne Bittman