Re: NANFA-L-- mollies and calcium
Thu, 24 Mar 2005 09:15:33 -0700

Hey Moon

One of the troubles of using "specific gravity" as a measure of salinity is that
it's actually a measure of density. You can find the precise SG of your water
by taking a volume of water, weighing it, calculating the density, and dividing
it by the density of water -- if you're smart, you work in Metric Units where
the density of water is one kg/litre. :) Otherwise it's ... what? 8.5 pounds
per gallon or something? I dunno. This is why the term "relative density" is
replacing "specific gravity." Relative Density-in-least makes sense -- the
density of the stuff relative to the density of water. "Specific Gravity"
implies that .. gravity changes in your fish tank?

As such, if you were to have a friend with a saltwater aquarium and swapped his
Instant Ocean with Folgers Crystals, the specific gravity of the tank would go
up. Anything soluble in water should increase its relative density, specific
gravity, whatever (well, some things could actually lower it...)

All this is the long way of saying that a hydrometer would measure Calcium
density as well as it would regular salt density. I have no idea what the
amount you'd want to shoot for would be ... and it may in fact be too low for a
hydrometer to pick up on accurately.

As I understand it, though, CaCl would dissasociate in water and you'd iwnd up
bonding your CO2 with the Calcium... I suppose you could use pH swing to measure
it .. but don't really know, off hand, how. . . . Anyone?


> Is their a way to measure the amount of CCl in you water the way you can
> measure the specific gravity of water that has NaCl in it? Also is there an
> amount
> to shoot for?
> Michael Hissom (AKA Moon)
> Lower Cape Fear River, Waccamaw Lake and river system, and coastal salt water
> and brackish water estuaries in the same location. (South Eastern North
> Carolina)
> I have access to the only natural Ocean Shore Rock out cropping in Coastal
> NC

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