Re: Apisto-plants balancing act

["David A. Youngker" <nestor10@mindspring.com>]

From: Bob Dixon
Sent: Sunday, October 10, 1999 1:59 PM


> ...Now I have this really clean water, and can adjust the
> electrolyte levels to <60ppm GH and <90µs conductivity.
>  But I want to provide a reasonable nutrient level for plants,
> also.  I have the Homegrown Hydroponics "six-pack" and
> it seems I should be able to build my own electrolyte mix
> and PMDD formulas to meet the plants needs at the
> restrictive TDS limits necessary for the fish.  For those
> not familiar with the sis-pack, it contains:
> 1)Calcium nitrate (CaNO3)
> 2)Potassium sulphate (K2SO4)
> 3)Potassium nitrate (KNO3)
> 4)Monopotassium phosphate (KH2PO4)
> 5)Magnesium sulphate (MgSO4)
> 6)Trace minerals mix, with Fe, Mg, Mn, etc.

>From what I've gathered on the UseNet groups over the last couple of years,
the Homegrown "6-pack" is designed with the specific intent of creating the
S-C PMDD formula, so I'd also assume the same degree of control over dosage
levels.

> Percentages by weight are given with each one(in the really
> fine print), but one of the kids carried off my magnifying glass,
> so I'm going to have to wait until I find or replace it to mix the
> exact ratios of stuff.
>
> Can someone take a shot at mixing some or all of these
> into useable formulas, one for water re-constitution, and
> one for a fertilizer used every couple days?  I will be
> making pH adjustments using HCl, unless something on
> this list will draw it down to 6.0-6.3 as part of the re-
>constitution thing.  I wont be injecting CO2, and light levels
> will be fairly low.

The mix ratios are contained on Eric's site, naturally enough.

The jump-off point is located at http://www.thekrib.com/Plants/Fertilizer/
for pretty much most of the archived discussions concerning Sears' and
Conlin's approach. The original mix ratios are listed at the bottom of the
report listed at http://www.thekrib.com/Plants/Fertilizer/sears-conlin.html
and the "updated" mix ratio at
http://www.thekrib.com/Plants/Fertilizer/pmdd-tim.html , top of the article.

This is a good starting point for mixing the initial formula. Be advised
that two of the ingredients included in the "6-pack" are *not* primary
ingredients; the calcium nitrate and monopotassium phosphate is included to
give you the ability to exercise some control over nitrates and phosphates
in the tank. The intent here is to *exclude* them as limiting elements
should conditions warrant, and their usage is determined by the algae
control approach outlined in the study itself.

As to a breakdown vis-a-vis water changes and daily dosing, the only thing
you really have to consider is "how much will it take to bring the change
water up to strength"...

-Y-

David A. Youngker
nestor10@mindspring.com
http://www.mindspring.com/~nestor10




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