re: Why do roots exist?

>Dr. Dave wrote:
>The only nutrients which 
>are needed in the water column are Mg, K, Ca and of course CO2. These 
>consistent for several different types of rooted macrophytes on many 
>different types of sediments.

This puts an interesting question up for me.

I'm looking into mixing up some PMDD in the near future to add to my nutrient 
injection manifold.  If I need to put the Mg, K, and Ca in the water column 
instead of under the substrate, it seems that I would do well to add them to the
water column separately in carbonate forms.  So where do you get hold of 
Magnesium (bi)carbonate, or KHCO3?  Should I be looking at other anions instead?
 Perhaps just go with the sulfates, iodides, or the chlorides?  I have a 
feeling the hydroxides wouldn't be a very good idea.

David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc. Dallas, TX USA
(214) 575-3443 (voice)  MSGID:       DAWB
(214) 575-4853 (fax)    Internet:    dwebb at ti_com
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