PMDD's and Mastergrow

Kevin Conlin wrote:

>I must confess that when I developed the original recipe I based
>the %Mg and K on the Tropica formula.  Since then I've reduced
>the Mg to 40% of the original value and cranked the K way way up.
Oh good, I'm glad I didn't dream it up. ;-)

>Because Tropica Mastergrow contains K, it's more than just a trace
>element mix; 

The bottle says "Fertilizer for Aquarium Plants", so I suspect they agree
with you.

>however, my experience suggests that it has too little K
>for us power growers.  Using Mastergrow with supplementary K2SO4 and
>KNO3 would probably work well for those who can't find a cheap
>commercial trace element mix.

I think whether it works without other supplementation is very much
dependent on the overall growth rate of plants in the tank, and how much K
and N are available from other sources.  I'm not disagreeing with your
approach, or your advice.  But I also know how many beginner aquatic
gardeners _start_ with high nitrate levels.  I think Tropica's approach is
the only responsible course for a commercial company to take.  

It's sort of like the arguments for and against soil substrates.  I am
fully willing to aknowlege that the experienced aquatic gardener can have
really impressive results with a soil substrate, and that many (if not
most)plants clearly do better in a soil substrate.  BUT at the same time, I
think it's usually safer for beginners to go the laterite/ liquid trace
element route, since I ASSUME that most of them will over stock and over
feed, under plant and under light.<g>

Sometimes we forget, here in the list, that by the time someone makes it to
this list, whether they seem like "newbies" to the really experienced folks
or not, that they are already light years beyond the "average" hobbyist.

Karen Randall
Aquatic Gardeners Association