Re: substrate Qs

> 1/2 inch of worm castings and peat is TOO MUCH organic material and
> too fertile. This would almost certainly lead to persistent green water
> problems. I would suggest 5% by weight of either worm castings or
> peat mixed with 60% ordinary sand and 35% of the Terra Stone clay.
> Also I would use a 1" layer of sand on top of that as a seal and
> either pebbles or a little gravel to help hold the plant stems in place
> during the initial planting.
	Thanks, Steve, for your response.  A couple more questions come
to mind: Are you suggesting mixing the organic material, the sand and the
clay together in one layer?  I initially thought I would separate the
orgaic material from the clay/laterite layer with a layer of sand/fine
gravel.  Does it matter? 

>  The Ca and K in the substrate are of
> little use to the plants. These nutrients must be in the water and
> should be supplemented regularly along with Mg at water changes or 
> in a daily regimen like PMDD or Dupla drops.
	Hmmm.  Why would nutrients like Ca and K in the substrate be of
little use to the plants? I would think that heavily rooted plants like
Crypts and Swords would be able to use these nutrients in the substrate
just as well as they would be able to use N, Fe Mg etc.  Is there
something about Ca and K (and presumably other nutrients) that makes them 
unavailable via root uptake?  What am i missing in the nutrient uptake
and transport theory here?

	BTW, thanks also for your posted tips regarding Ca defieciencies
in Swords:  my Swords have improved colour since I began adding small
amounts of Dolomite powder occasionally.  My Jade Sword is beginning to
regain its former dark (jade) green colouration.  I haven't seen any
negative results of adding the powder directly to the water column, though
it does of course take a long time to dissolve.

PS  Does the company which ships the terra cotta clay not have available a
chemical breakdown of the clay?