To: aquatic-plants at actwin_com
Subject: PMDD, Etc.
From: STDIXON <stdixon at bechtel_com>
Date: Thu, 30 Jan 1997 11:39:34 -0500 (EST)
Cc: Steven Dixon <stdixon at bechtel_com>, Maureen Theberge <mtheberg at bechtel_com>
Mr-Received: by mta SFMW.MUAS; Relayed; Thu, 30 Jan 1997 11:39:34 -0500
Mr-Received: by mta SFP2; Relayed; Thu, 30 Jan 1997 11:39:50 -0500
Paul Sears wrote:
> If they have no nitrate in their tap water, they are short
>of K, trace elements or both. I wish people would _read_ what we
>wrote rather than using another fertilizer recipe blindly. Only
>add the nitrate if you can drive the tank nitrate to unmeasurable
>levels. This is not difficult.
I did read what you wrote carefully :-) and here's what confused me: Under
Recommendations there is a 4 item list for optimizing plant growth. Items
#1 and #2 were easy: set the light and CO2 levels and add some
iron-containing trace element mix. Item #3 says, once you reach the target
Fe level, check the nitrate level. "If nitrate levels are below 2 ppm,
proceed to the next step [which is adding nitrate]." In other words, don't
add any potassium sulfate (K2SO4).
My nitrate levels have been close to zero for over a year (my plant growth
has been pretty marginal too, but then I haven't had an algae melt down
either). So starting with less than 2 ppm nitrate, I wouldn't have added
any potassium following the recommendation.
But I didn't follow the recommendation. I noticed that in Case #1 K2SO4
was added with a resulting reduction in nitrate (suggesting K deficiency)
and I also noticed that the PMDD recipe was heavy in potassium (more than
2g of K2SO4 for each g of KNO3). So I asked myself, what are the sources
of potassium in my tank? The answer was none except for a trace in my
trace liquid and whatever I get from fish food. So I added K2SO4 in a 2:1
ratio with the KNO3--with wonderful results :-) :-).
What the paper doesn't tell us is how to tweak potassium. Once we
establish 2-5 mg/l nitrate, if increasing the K2SO4 input further results
in a reduction of nitrate levels, doesn't this suggest a K-limited, rather
than the P-limited, condition we're striving for? Recommendation Item #5
for the paper?
Paul Sears also wrote:
> I think the problem is that [fertilizer] has been something close
>to a black art for a very long time. "Fertilizers" and other additives
>with unlisted ingredients, lots of conflicting stories about what causes
>what, and an appalling ignorance of basic chemistry have left almost
>everyone in the dark, hoping to find a set of conditions that lets
>them keep a half-way decent looking aquarium.
> It does not have to be like that!
Three cheers for that sentiment! Now, why don't we take a respite from
PMDD and Tropica MasterGrow, and try to figure out what Amano is doing?
Why don't we buy samples of all of his stuff: PowerSand, Green Mix this and
that, Special Hocus Pocus Goop A, B and C, and whatever else :-), and try
to figure out his methods? Why not move his knowledge out of the Dupla
(secrecy) corner, as fast as we can. We all crave "pristine" planted
tanks, right? And isn't Claus Christensen (Tropica) right? Shouldn't we
all know what we're putting into our aquariums?
If any of you chemistry/science types were interested in determining the
ingredients of Amano's stuff, I will send you a check for $50 to help with
the lab costs. I really mean it. Maybe his stuff is just another brand of
Ibuprofen (N,P,K plus a mix of iron and other trace elements), but what if
he's on to something new? He's a pretty original guy, I think. (I want to
think about this a little bit more, but I don't think there's anything
illegal, immoral or improper about determining the ingredients in Amano's
products. We buy them; they're ours. Could it be that simple? I've kind
of already made a little promise to myself not to buy any product that
doesn't list the ingredients (with relative amounts). I was pleased to see
that SeaChem Flourish now comes with a list of ingredients with
percentages. We need to send a message to the aquarium business community
on this point. It's a little bit like copy-protected software--it's just
not user friendly. This hobby is hard enough without playing a constant
guessing game with the people we are willing to pay to help us.)
On a personal note, in the past I traveled in Japan (for work) on numerous
occasions, and I never knew to take the train north to Niigata--to see the
Great One's beautiful aquariums. Oh, how I wish I had done that!
Correction from yesterday: On page 176 of The Optimum Aquarium, the
nitrate level for the large Dupla aquarium is listed as 25 mg/l. Whow!
Regards, Steve Dixon