Re: [AGA-Member] Magnesium nutrient issues

[Jeffery Ludwig <jeff@rockytop.net>]

> I am also not sure about your magnesium ratios you are
> trying to chieve. CA and MG are macro elements. The
> plants use them for osmotic balance as well as
> consuming themin trace amounts. The ratios between CA
> and MG are usually 4:1 or 3:1. I think what you read
> on Chuck's page was the minimum amount of 5-10 ppm MG.

Just a few questions/comments on top of Larry's excellent reply... where 
did we collectively come up with this 4:1 or 3:1 ratio in the water 
column?  I understand thats the ratio in dry plant matter, but that 
doesn't logically mean we need 4:1 or 3:1 in the water column.  At the 
conference Bailin and I were taking about this, I had thought the ratio 
was 4:1 Mg:Ca not Ca:Mg... I tried flipping this when I got back by 
adding Ca (I have very soft water) with disasterous results really, 
plant growth really slowed down.  I re-upped the Mg once again and now 
things are back to normal, I'm closer to 1:1 or even heavier in Mg. As a 
second "data point", one of my tanks has Flourite, had the worse 
problems.  The other tank is Eco-Complete, which I've been told leeches 
Mg didn't have any algae issues but growth did noticeably slow down.

Anyhow, my personal experience has been contrary to the "conventional 
wisdom" on Mg levels, YMMV, etc, but as far as I know no one has 
actually done a controlled experiment so I would tinker with the levels 
to see what works best for you...

Jeff Ludwig
Elkton, MD
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