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PMDD: Sources and Doses Round 2

In response to questions on PMDD, here's
an update on my post on where to buy PMDD
(poor man's dosing drops) and how to use it.
Hope this helps (many thanks to those who made
comments, sorry this has gotten so dang long):

A)  Sources for a chelated trace mix:

1)  Plantex's "CSM"   1-905-793-7000   $30 US for 5Lbs
    314 Orenda Ave, Brampton, Ontario
    L6T1G1 Canada
    (Thanks to Kevin Conlin)
    For breakdown, see part E

2)  Miller Chemical & Fertilizer's "Microplex"
    Hanover, PA
    Distributor: NitroPhos 1-713-530-5558
    (Thanks to Doug Skokna)
       I've never tried Microplex, but it has;
         Mg-5.4%         Bo-0.5%
         Co-0.05%        Cu-1.5%
         Fe-4.0%          Mn-4.0%
         Mb-0.1%         Zn-1.5%

3)  Some Hydroponics and local garden shops
     have trace mixes. But, check their ingredients
     list to make sure they do not have N, P or K
     (i.e. just trace mix, not something like
     Miracle Grow), they're chelated, and that
     their trace percents are similar to CSM.

     Some folks feel Cu (Copper) should not be included
     in a PMDD trace mix (it can be quite toxic to plants
     and fish in high concentrations). It is in Microplex
     and CSM. I haven't had any problems with CSM though
     I do change 25% water a week. I know many have had
     success with Microplex too. If you use another trace
     formulation, you might want to be sure its Cu isn't
     to high.

B)  Sources for MgSO4 and H3BO3

1)  MgSO4 is available from just about any drug
    store as Epsom Salts. $2 buys a lot. Note it's
    hydrated (the form PMDD calls for) so it's
    formula is MgSO4 + 7H2O.
    (Thanks to Karen Randall)

2)  H3BO3 is Boric Acid, a source of Boron. Also
    available from drug stores, a couple buck buys
    around 250mG, a lot.
    (Thanks to Paul Sears)

C)  Sources for KNO3 and K2SO4

1)  ECO Enterprises  1-800-426-6937
    1240 NE 175th Street, Seattle WA
          KNO3   $5.98/ 5 lbs   Agro grade
          K2SO4  $5.98/ 5 lbs   Agro grade
          (Thanks to Doug Skokna)

2)  PCI Scientific Supply
         KNO3   $16.75/500mG  Lab grade
         K2SO4  $15.50/500mG Lab grade
         (Thanks to Tom Polk)

3)  Local Hydroponics and Garden Supply shops.
         Note: Greenlight's "Stump Away" is pure KNO3         .

5)  Home Grown Hydroponics
    (Thanks to Suwat Phruksawan & Louis Lin)
    I've not checked them out

D)  Source for complete pre-mixed PMDD per original
    Conlin-Sears formulation:

1)    Neil Schneider, Poway CA, PacNeil at worldnet_att.net
      $30 for dry ingredients to make 5 liters of PMDD.
      (Thanks to Neil for making it easy)

E)  How and Why to roll your own PMDD with Plantex CSM:

1)  As noted by Tom Polk, Plantex's new CSM has no
    B (boron) and therefore needs to have some added.

     For a ratio of 7Fe to 1.26B (5.5 to 1)
       - mix 14 parts CSM to 1 part H3BO3 (Boric Acid) by
         weight (about 10.5 tspns of CSM to 1 tspn H3BO3).

     Here's the breakdown of CSM before and after adding Boron.
       Regular CSM         CSM+B
       Fe    7.0%            6.53%
       Mn    2.0%            1.87%
       Mg    1.5%            1.40%
       Zn    0.4%            0.37%
       Cu    0.1%            0.09%
       Mo    0.05%           0.05%
       B     0%              1.18%
       Co    0%              0.00%

2)  Sears and Conlin's latest PMDD formula: mix
     with water to make a 500mg solution,
      1 tspn trace mix "CSM+B"
      1 tspn MgSO4+7H2O
      2 tspn K2SO4
      1 tspn KNO3   (more or less, depends on your nitrate)

    Some mixing notes:
       - Some kinds of agro grade K2SO4 give off a gummy black
         goo when mixing. Just remove it best you can by wiping
         it off your mixing tool.
       - The CSM+B should be completely dissolved. Try crushing 
         any undissolved crystals with you mixing tool.
      -  The KNO3 may have trouble becoming completely soluble
         and a fine particulate will settle on the bottom. That's ok,
         just shake the PMDD before use.
      -  Some say to mix up PMDD with distilled water. I've found
         regular tap water works ok for me.
      -  Why add the MgSO4 when CSM now has Mg (it didn't use
         to)? CSM doesn't have enough Mg to meet PMDD ratios.

    And yes, with the dry chemical quantities you no doubt have
    acquired, you could make enough PMDD to fertilize Lake
    Erie <g>.

3) So why bother with PMDD when you can buy products like
    Flourish, Dupla Drops, Terrafit, etc?
     - Well. . . try them. If you meet with success at a
       reasonable price, great!
     - While requiring an initial outlay, PMDD is cheap over the
       long run (hence, PMDD: poor man's dosing drops).
     - PMDD trys to provide a balance of fertilizers. Not to
       cast aspersions, but it's more than "Iron Water".
     - With PMDD, you know what you've got. As you gain
       experience, you can experiment.
     - It yields results comparable to some far more
       expensive brews.

F)  How to store PMDD

<<<  I'd be sure to keep PMDD chemicals   >>>
<<<  away from the kids !  Some are nasty.>>>

1)  Unmixed PMDD constituents are stable enough.
    The chelated trace mix should be kept dark, dry
    and not unduly hot.

2)  Some say mixed PMDD will degrade over time and
    even develop mold. Things that help:
     a) Put your PMDD in a dark brown or opaque
        bottle. Light can destablize chelates.
     b) I refrigerate my main stock (mark it well so someone
        doesn't take a swig) and leave a small 50ml bottle
        by the aquarium for convenience.
     c) Since dry ingredients are more stable, only
        mix up a few month's worth of PMDD at a time.
     d) Some people add a little HCL to the brew; never
        tried it myself.

G)  How to dose PMDD

    Track Fe and NO3 with test kits and watch how
    plants and unwanted algae respond. It takes
    awhile (weeks) to safely ramp up and stabilize
    fertilizer concentrations. More PMDD is not
    necessarily better and, although somewhat
    fault tolerant, too much too fast can be
    injurious to plants and fish.

2)  As a starting point, for each ten gallons of a heavily
    planted, well lit, CO2 injected tank with 25% of water
    changed each week, try around 1/4 ml of PMDD
    a day. So, for a 29 gallon tank, start with 3/4 ml PMDD
    a day. If you don't change as much water, you might
    want to dose less.

3)  Many seem to recommend dosing PMDD to maintain
    around 0.1mG/ltr (0.1 PPM or Parts Per Million)
    concentration of Fe (Iron) in the aquarium
    and letting the other element concentrations
    fall where they may. Consensus is exceeding 0.2mG/ltr
    Fe is counterproductive. Again, expect to take awhile
    to build up to a 0.1mG/ltr Fe level.

    So, what if use of laterite raises your Fe levels too?
    I'm not really sure though I use laterite, limit PMDD
    doses to keep overall Fe levels below 0.1mG/ltr, and
    still achieve ample fertilizer concentrations.

    Suspecting that to much Fe can promote algae growth,
    Steve Pushak notes he only adds sufficient Fe
    to keep plants growing without symptoms of chlorosis
    or iron deficiency (yellow or pale leaves), a level that
    may fall under .1 mG/ltr Fe. He has found Salvinia to
    be a good indicator plant for Fe dosing.

    Oh, SeaChem, Red Sea, Tetra, Dupla, Hach,
    LaMotte all make Fe test kits. Prices and ease of use
    very widely, I like the pricey LaMotte myself. Try
    "That Fish Place"; 800-733-3829 or
    "Pet Warehouse"; 800-443-1160.

4)  The target for NO3 (nitrate) is said to be about
    5mG/ltr (5 PPM). If your aquarium NO3 already
    exceeds 5mG/ltr, you ought to initially reduce or
    eliminate the KNO3 from the PMDD formulation.
    You might notice, however, that as PMDD begins
    to balance things out by providing other fertilizer
    components, your levels of naturally occurring NO3
    will fall to the point where you'll need the KNO3.
    Though, if you do ultimately reduce or eliminate KNO3
    from the mix, don't worry about having also reduced
    the K. The K2SO4 seems to provide enough.

    Many of the folks that make Fe test kits also make ones
    for NO3. Check that they're accurate in the 5mg/ltr range.

5)  I don't know what a good target for K (potassium) is.
    It turns out to be really difficult to measure anyway.
    Since PMDD is rich in K, and I've read you can have a fair
    bit of excess K without harming aquatic life,  I wouldn't
    worry about it.

6)  PMDD has no P (phosphate). According to work by
    Sears and Conlin, having the P in N-P-K as your limiting
    major fertilizer factor helps reduce algae. Of course plants
    require some P (.02 mG/ltr a good target), but you'll no
    doubt have more than enough supplied by fish food and
    the like.

    Most terrestrial plant fertilizer supplements have a lot
    of P. They may also have N in the form of NH4 or NO2
    (quite toxic to fish unless dosed very very carefully). That's
    why the advice to not use otherwise fine products like
    Miracle Grow.

 7)  Why daily PMDD doses rather than a weekly mega-dose?
      -Some constituents of PMDD are not terribly stable (like
       chelated Fe) and may loose potency in the aquarium over
       the course of a week.
      -You avoid concentration "spikes" that fish might not
      -Even if PMDD fertilizer ratios aren't perfect for your
       situation, you will have at least some of whatever your
       limiting factor is available each day.

  8)  Most drug stores sell droppers marked in mL for
      dispensing medicine. The 2.5 to 5mL sizes work
      great for metering out PMDD. Oh, when dosing,
      I'd first shake the bottle in case of settling, then
      try to stir the PMDD slowly into the aquarium so
      fish don't get hit with a "chemical cloud".

H)  Some of my dosing experience

    Did I follow my own advice and go slow . . . no. <g>
    I initially dosed with 5ml PMDD a day in my
    45 gallon tank (40 gallon water column).
    I changed 25% of my tank's water each week.
    If you assume no Fe depletion (a poor assumption
    but good for establishing an upper bound) my
    Fe concentration would have eventually leveled
    off at 0.4mG/ltr. Too high! So, once I reached Fe of
    0.1 mG/ltr (took about 2 weeks at the 5ml dose), I
    reduced my PMDD dose to a little over 1 ml a day.

    My plant growth really improved.    :-)

I) PMDD constituents

PMDD s breakdown by element:
  approx G/Ltr  % of total  Ratio to Fe
N       1.41    6.41%        3.06
K      13.80   62.53%       29.84
S       5.19   23.50%       11.21
Mg      0.95    4.32%        2.06
Fe      0.46    2.10%        1.00
Mn      0.13    0.60%        0.29
Zn      0.03    0.12%        0.06
Cu      0.01    0.03%        0.01
Mo      0.00    0.01%        0.01
B       0.08    0.38%        0.18
Co      0.00    0.00%        0.00
And two important quantities
NO3     6.26    --          13.54
SO4     15.56   --          33.63

J) Nerd stuff on calculating aquarium
    PMDD constituent concentrations.

1)  Figuring the change in aquarium concentration of Fe
    (or any element) after a single PMDD dose:

Increase in Concentration in PPM =
(PMDD concentration of element)*(Dose)/(water column)
      in mG/ltr or PPM            in ltr       in ltr

   my case: 5ml PMDD, 45 gallon tank (40 gallon
   160 liter water column), and Fe is of interest.

[(0.46G/ltr)*(1000mG/G)]*[(5ml)*(ltr/1000ml)]/(160ltr) =

_0.0144 mG/ltr Fe_  increase in aquarium as a result of a dose.

    Of course, to figure it out for multiple daily doses (no
    water changes), multiply by the number of doses.

2)  Figuring the cumulative change in aquarium concentration
    of Fe (or any element) in PPM after long term daily PMDD
    use with periodic water changes:

    The tricky part about figuring this is knowing depletion rates.
    I can figure out how water changes will deplete an element,
    but I don't know how much plants will. Well, since my intent
    is to avoid overdosing Fe, I'll look at the worst case: one
    where no Fe is used by the plants (sure, a rotten assumption
    since the whole point is to provide Fe, but it does yield an
    upper bound or maximum possible concentration).

    Turns out concentration buildup given periodic water changes
    is one of those Geometric Series things.

    Say "D" is the total concentration increase after multiple PMDD
    doses preceding a water change (figured in PPM per part 1).
    Say "R" is the portion of pre-change concentration
    that remains after the water change (ie a 25% water change
    leaves 75% of concentration). Well, after 6 weeks,
    you'd have a cumulative concentration of:
        (((((D*R)+D)*R+D)*R+D)*R+D)*R+D or
        D*R^5+D*R^4+D*R^3+D*R^2+D*R+D or
        SUM n=0 to 5 of (R^n+D)
    Now, over many many weeks you'd have a cumulative
    concentration of;
        SUM n=0 to infinity of (R^n+D)  or
        D/(1+R)     Simple result, huh? 

    So, using this secret formula D/(1+R) and putting it in
    terms of daily doses, days till water change, and % water
    change (note: % water change = (1+R)):

Long Term Cumulative Increase in Concentration =
(daily increase from dose)*(days till change)/(% water change)
    in mG/ltr or PPM               in days       in decimal
                                             only valid if water volume
                                             change >> dose volume

    Carrying over the example from part 1): 5 ml PMDD dose
    daily, but with 25% weekly water changes;

 (0.0144 mG/ltr Fe)*(7)/(0.25) =

 _0.4mG/ltr Fe_  final aquarium concentration

    Yikes, 4 times too high! That's why I ended up leveling
    off at a lower PMDD dose, about 1 ml a day, for my 45
    gallon tank.

    Again, this all assumes no depletion, a lousy assumption,
    so I'd measure Fe as you go. As I said, this calculation is
    only good for an "upper bound".

K)  So, just add PMDD to your water column and your plants
    will grow like weeds? Well . . . maybe. There are other
    factors to investigate. Some feel substrate fertilization is key
    to success with some plant species. Others swear by CO2
    injection, or VHO lighting, or substrate heating, or laterite. If you
    made it this far, you're probably one of those folks that just
    can't learn enough about this stuff.  :-)         Use your Web
    browser to check out the aquatic plants section of the Krib at 

    Tim Mullins - Pittsburgh
    If you spot mistakes or have comments, please post or e-mail