🚀 go-pugleaf

I was looking at Martin Moe's Marine Reference book and I'm puzzled by
his dKH conversion (cf. p. 36) . Sea water should have ~400 ppm Ca+2 ions or 
equivalently, ~1000 ppm CaCO3. Now if I take his conversion to dKH I either 
divide ppm CaCO2 by 17.9 or multiply by 0.05 (I'll forgive his approximation 
0.05 ~1/17.9). If I follow his prescription and divide by 17.9 this means I 
would get a dKH for sea water of 

		(1000 ppm CaCO3)/17.9 ~ 56 dKH.


From his comments on p. 36 and from other sources it's clear that sea water 
should have a dKH of less than 7. So what's going on here? I suspect a typo
somewhere. I don't think that his conversion is from Ca+2 instead of CaCO3 
because this would result in 

		(400 ppm Ca+2)/17.9 ~ 22 dKH

which is still too high. Does anyone know what the correct conversion is? Or
am I just being stupid here?

Fernando Pineda (fernando@aplcomm.jhuapl.edu)