Re: Sears and Conlin paper

On Wednesday, 3 April 1996, Aquatic-Plants-Owner at ActWin_com wrote:

> First, do you have the  final concentrations (in aquarium) of the 
> nutrients in PMDD.  We need to start talking about final concentrations, 
> and not just relative levels or concetrations in a fertilizer mix.  Its 
> calculatable from the info in your paper, just wondering if you have it 
> handy.

If you dose for the recommended 0.1ppm Fe, you'll get about 0.5ppm Mg,
0.02ppm B, 0.03ppm Mn, 0.001ppm Mo, 0.006ppm Zn, and 0.001ppm Cu.
K and N depend on tuning; the base PMDD provides 1.3ppm K and 0.6ppm NO3.
Since only Fe is being measured, there's no way of knowing exactly how
much of the other trace elements are in solution.  Additional trace
elements come from the fish food.  We don't think absolute concentrations
are as important as simply having more than enough for the amount of
phosphate available.  Excess elements are removed through regular water

> Second, do you have any ideas on why many people (ie Dupla users) can get 
> good results without additional N (other than fish food).  I think would 
> be an interesting topic for the Discussion.

This issue is complicated by substrate additives such as laterite.  There
is no way of knowing (for me, anyway) what these additives contribute other
than iron.  In a tank with a relatively inert substrate, using the Dupla
water conditioners, tablets, and drops, I would expect that tanks with
a low fish load would do relatively poorly due to trace element and
macronutrient deficiency.  With a moderate to high fish load, the fish
food would provide the trace elements and macronutrients, and the plants
would do fine.  However, the food would provide excess phosphate, so the
algae would also prosper. I predict, with tongue firmly in cheek, that there
is a high probability of finding SAEs in Dupla tanks.
Kevin Conlin   kcconlin at cae_ca   "We're Canadians.  We HAVE to be polite"
Finger as332 at freenet_carleton.ca for PGP public key.