Question on balanced alk/calc

[kevin2000]

I would appreciate some guidance -

I have read most of your articles and seem to have trouble understanding some info in your last article discussing reasons that alk & calc get out of balance.

In particular I am having trouble with the balance of 1 meg/l of alk to 20 ppm of calc. -- might be my poor knowledge of the metric system but this ratio would seem to conflict with your Water Parameters article which indicates that natural seawater has an alk level of 2.5 meg/l and a calc level of 420.

Any assistance would be appreciated.

Thanks

[Randy Holmes-Farley]

The ratio of 1 meq/L alkalinity per 20 ppm calcium is the ratio that is removed as calcium carbonate is deposited.

The ratio of 2.5 meq/l alkalinity to 420 ppm calcium is the ratio present in seawater. There is no reason that the ratio in seawater would match that from the precipitation of calcium carbonate, and in fact, it doesn't.