Re: Aquatic Plants Digest V2 #277

> From: James Wong <u2120863 at acsusun_acsu.unsw.edu.au>
> Date: Fri, 25 Oct 1996 12:31:45 +1000 (EST)
> Subject: Toxicity of potassium and magnesium?
> Hello fishfolks,
> I wondering if any of you out there know the toxicity of either potassium 
> sulfate or magnesium sulfate. Specifically, up to what levels can these 
> substances (Mg, K and SO4 ions) be considered safe in an aquarium. This 
> question does not seem to have been addressed in the archives.
> Thanks in advance

There was a very brief spiel about K in a practical aquariums and water 
gardens a while back. From memory the author belived that it could easily 
reach 50ppm without problems and perhaps more. It is pretty easy to find 
and add anyway, I usually add about a half teaspoon to my 120L tank with 
a water change and then have some in a PMDD type recipe as well.

Peter Hughes