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Re: Kevin's RO recipe

On Tue, 30 May 2000, Kevin Zippel wrote:

>     When I was at the Bronx Zoo, where we had bad water from the tap and
> copper plumbing, I tweaked Roger's recipe a little using ingredients that
> were most easily dissolved.  Here's what I finally settled on:
> 100 gallons of RO water
> 15.0 g calcium chloride  CaCl2
> 17.6 g magnesium sulfate  MgSO477H20
> 13.6 g potassium bicarbonate  KHCO3
> 11.3 g sodium bicarbonate  NaHCO3
> 0.5 g commercial trace element mix (Homegrown Hydroponics)

I think this is an excellent alternative.  I developed a very similar
recipe that differed mostly in the sodium bicarb content.  I wanted 3
degrees of alkalinity and provided it by using twice as much sodium
bicarb.  The resulting ratio of Na:(Ca+Mg+K) is 1:2 and the total
dissolved salt content is a little higher.

I haven't talked about the recipe, mostly because I don't have a good
means for most people to determine how much of the various constituents to
use.  Most of us don't have a good scale and several of these constituents
are hygrscopic anyway, which means they take on water from the air and
their weight varies.

One option is to start by mixing concentrated solutions of each of the 4
main ingredients.  I think the solutions should stay stable as long as
they're sealed.  Then use simple test kits to figure out how much of each
solution you need to add to get about the right result.

Add enough epson salt solution to create 1 degree GH
Add enough CaCl2 solution to increase GH to 3 degrees
Add enough KHCO3 solution to create 1 degree alkalinity
Add enough NaHCO3 solution to increase the alkalinity to 2 degrees.

(for my variation, you would add enough NaHCO3 to increase the alkalinity
to 3 degrees).

The hydroponics mix is a nice addition, especially if you're using a
simple substrate and/or incomplete fertilizers.  If you are already using
PMDD or a complete fertilizer then the hydroponics mix may not be needed.

Roger Miller