re:Carbonate hardness

>From: MGW925 at aol_com
>I have a 55 gal tank, temp 80 F, ph=6.4/6.6, no ammonia, no nitrites, slight
>measure of nitrates, no phosphates.  With a tetra kit, the GH took 3 drops
>and the KH took 1 drop to make the described color changes.  I admit
>confusion about the measurement:  degrees? ppm?

For the Tetra kits, one drop = 1 dGH (degree of German Hardness).  If you want
to get fractions of degrees, double, or triple the amount of water and assume a
proportionate increase in drops per dGH.

I thought it was 17 ppm = 1 dGH, but someone else posted the actual value
recently and it's closer to 18 ppm = 1 dGH.

David W. Webb in brrr-chilly, Plano TX.