Re: Mg addition

On Tuesday, 12 November 1996, David T. Gauthier wrote:

> About one month ago, I switched to full-blown PMDD with MgSO4.  Result:
> Echinodorus spp. took off, growing out of the tank; C. wendtii looking
> better; Rotala indica indifferent; H. difformis showing deformation and
> curling of new leaves; Lilleaopsis spp. stopped growing and is getting
> overgrown with hair algae.  Hair algae on Echinodorus and C. wendtii
> decreased noticeably.  A few horticulturalist friends looked at my
> plants and said that symptoms were similar to nitrogen or magnesium
> overfertilization in fast growing terrestrials.

What is your iron concentration?  Nitrate concentration?

I've decreased the amount of MgSO4 in my PMDD recipe and increased
the macronutrients.  I didn't decrease the Mg because I suspected Mg
toxicity, but rather because I didn't notice any difference when I
reduced the amount.  My current recipe is 1tbsp trace element mix,
1tbsp epsom salts, 1tbsp KNO3, and 2tbsp K2SO4 in 500ml H20.  Paul
and I are in the process of updating our paper.

H. difformis seems to be really sensitive to trace element
overfertilization.  My suspicion is that you've overdone the trace
elements a bit, hence the question about your iron concentration.
Kevin Conlin  Montreal, Canada  "We're Canadians.  We HAVE to be polite"
Finger as332 at freenet_carleton.ca for PGP public key.