re: PMDD questions
---------- Forwarded message ----------
From: psears at emr1_NRCan.gc.ca (Paul Sears)
Subject: Re: PMDD questions
To: Aquatic-Plants at ActWin_com
Date: Wed, 12 Feb 1997 11:36:54 -0500 (EST)
> From: "CORBEIL, SCOTT" <corbels at macmail_mcgawpark.baxter.com>
> Subject: Enigma
> I have a 150 gal. heavily planted tank, fertilized with CO2 and PMDD. =
> Nitrates are 5-6 ppm, Fe is 0.5 mg/ml, GH =3D 120-130 ppm, Ph is 6.4-6.6, =
> phosphate level is below 0.1ppm. The weird thing is every time I do a =
> water change I suddenly see a burst of activity in my plants, i.e. the =
> plants release oxygen bubbles like crazy. This, to me, indicates a =
> nutrient deficiency but I can't figure out what it could be. Any =
The same thing happened in Kevin's tank, so we tried a couple
of experiments. It isn't a shortage of nickel or cobalt. It now occurs
to me that one might use up all the calcium in soft water, so we should
try that too. If I remember correctly, Kevin tried NaCl, so it isn't
either of those ions, either.
The water going into the tank would be expected to have a fair
bit of dissolved gas, if it came from a cold water main, but I wouldn't
expect it to be enough to produce the sort of effect Kevin regularly
saw (and still sees, Kevin?).
> From: "Williams, Rochelle - DCSPIM" <williaro at ftmcphsn-emh1_army.mil>
> Subject: K2SO4 and PMDD
> Just got the chelated micronutrient mix today and I'm almost ready to mix
> up a batch of PMDD. I'm only missing the ingredients that give the K. Can
> KCl be substituted for K2SO4? If so, what is the correct ratio?
KCl is 52.3% K, and K2SO4 is 44.8% K. To get the same amount of
K, use 85.7% as much KCl as you would K2SO4. Mind you, I can't see that
a 15% change in anything is going to make much difference, so using
the same amount would do.
> From: Michael Stone <mstone at dekalb_dc.peachnet.edu>
> Subject: PMDD & Nitrate level
> Good day all,
> I was reading over the PMDD protocol by Sears & Conlin and I was unsure
> about one aspect of the nitrate target reading. I could not find any
> indication in the original post or follow-ups as to the type of test kit
> used or how the results were reported. Is the target 5-10ppm Nitrate
> reading Nitrate-nitrogen or Nitrate ion? I have two kits (Seatest FW &
> LaMotte) that measure Nitrate-nitrogen and one (Seachem) that measures
> Nitrate ion. I understand the difference between the two and how to
> convert between them, but I need to know which it is. Pardon me if this
> has already been covered.
It is nitrate. To specify nitrogen, one would normally say
nitrate nitrogen, as you did.
Paul Sears Ottawa, Canada
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