re: PMDD comments

---------- Forwarded message ----------
From: psears at emr1_NRCan.gc.ca (Paul Sears)
Message-Id: <9701311357.AA14406@emr1.emr.ca>
Subject: Re: PMDD comments
To: Aquatic-Plants at ActWin_com
Date: Fri, 31 Jan 1997 08:57:02 -0500 (EST)

> From: STDIXON <stdixon at bechtel_com>
> Subject: PMDD, Etc.
> 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).  

	You're right, that part needs to be rewritten.  There should be
a part of #2 that refers to K2SO4 addition.  Thanks for pointing it out.

> So I added K2SO4 in a 2:1
> ratio with the KNO3--with wonderful results :-) :-).

	I'm glad to hear it!  :)

> What the paper doesn't tell us is how to tweak potassium.

	That is because we didn't know.  These days, I watch the older
leaves on the hygro and on some small swords.  If they get holes (hygro)
or become transparent (swords) I add more K2SO4.   The appearance of
algae is also a good indicator.
> 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?

	Something like that seems appropriate.

> Paul Sears also wrote:
> >	I think the problem is that [fertilizer] has been something close
> >to a black art for a very long time.  

	I meant keeping aquatic plants, not just the fertilizer aspect of it.

> 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?  

	I'm more interested in experiments than trying to copy methods
that someone else isn't disclosing.  

> And isn't Claus Christensen (Tropica) right?  Shouldn't we
> all know what we're putting into our aquariums?  

	Yes!  If we don't know what we are putting in, we are staying at the
black art stage.

> This hobby is hard enough without playing a constant
> guessing game with the people we are willing to pay to help us.)

	I don't think it _is_ that hard to have a pretty impressive tank.
_Some_ of the manufacturers and a lot of the retailers would like you
to think so.  If they want to make a lot of money, it's important that
you stay confused.  Maybe I'm being hard on the retailers - most that
I have talked to are pretty confused themselves.

> 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!

	If it is in Europe, the water that goes in probably has 30-50 mg/L
nitrate.  One wouldn't need to add much (any?) KNO3 there. Do water changes
to keep the nitrate up!!!   :)

Paul Sears        Ottawa, Canada

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