Hardness Equivalents

["Darren J. Hanson" <djhanson@calweb.com>]

>Just a quick question and thanks in advance. How do you convert ppm into
>microsiemens or German degrees of hardness. Is there a formula for this ?

Risking sacrilidge here, but quoting from "The Marine Aquarium Reference:
Systems and Invertebrates" (c) by Martin A. Moe, Jr. 1989, 1992 (who spoke
at a local aquarium society last year), page 36:

Part I. The Marine Environment

    Chapter 1. The Chemical Environment

        Table 2. Hardness Equivalents

        Unit                                    Equivalents in ppm CaCO3

        1 meq/l                                                 50.0
        ppm CaCO3                                                1.0
        1 grain CaCO2 per US Gallon                             17.1
        =B0Clark, English, 1 grain CaCO3 per Imperial Gallon      14.3
        10 ppm (France), 10 ppm CaCO3                           10.0
        dKH, =B0KH, KH or dH, German, 10 ppm CaO                  17.9

        To convert meq/l to ppm CaCO3                   multiply by 50
        To convert meq/l to dKH                         multiply by  2.8
        To convert dKH to meq/l                         divide   by  2.8
        To convert dKH to ppm                           multiply by 17.9
                       to =B0Clark                        multiply by  1.25
        To convert =B0Clark to ppm                        multiply by 14.3
                          to dKH                        multiply by  0.8
        To convert ppm to =B0Clark                        multiply by  0.07
                       to dKH                           multiply by  0.05

What can I say, this book has been the best reference I've ever found to
fish tanks, regardless of whether they are fresh, brackish or saltwater. It
goes into great detail about all different physical aspects that can affect
your fish & plants (light, water chemistry, substrates, etc) as well as the
most complete anaylsis of all the different types of filters made that can
help maintain the desired environment. I can't recommend it enough for
ANYONE who keeps fish, regardless of what kind they're keeping!

- -- dj