You could always "calibrate" the test yourself: get a sample of water with no Ca (i.e. RO) and add a fixed amount of Ca to it. Now test that water
using both methods (and to be "scientific", test a third "control sample" with no added calcium) and see which reads the proper amount against the
given test colour. I'd recommend using CaCl2 rather than Ca(OH)2 for this test since it's already in solution and Ca(OH)2 isn't that soluble so you'd
have to use a super tiny amount that would be hard to weigh precisely. You'll need to remember some HS stoichiometry of course! I've done this before
and it works well (haven't tried it specifically w/ Ca though). Just my 2cents



i agree, the drops always turn colour on the top bit of water b4 u shake it
anway. and then changes all of the water colour when u shake it

i dont think it would even posable to have the water change colour b4 u
shake it cos it will always change colour when u shake it b4 adding the next
drop

"Mort" wrote in message
m...

I'm no expert, and from the sound of it, neither is the LFS owner.

In other words, I think that guy is wrong but I'm sure someone else can
verify that like boomer.

hth

~Mort

"Nighthawk" wrote in message
news:1K56d.549864$gE.276499@pd7tw3no...

Well this might sound like a dump question from the subject but am kind
of
confused.

I went to the LFS to get a calcium test kit and this time i am buying the
SeaTest test kit and after a brief conversation with the owner. he told

me

to test it correctly and i asked him what do u mean by correctly. He said
when you add the reagent drop by drop to count how many drops, i should

stop

when the drop hit the solution in the test tube ( not after you shake or
swirl until the reagent has mixed in well with the rest of the test

water ).

As far as i know, if the reagent is to react with all Calcium ion in the
test solution, i should be swirling and shake it to make sure all Calcium
ions are reacted to get an accurate reading rather than on at the top
portion when the drop hits the water and turns blue.

Can someone shed some lights on this.

Thx in advance for any help.