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reagent have slight higher specific gravity but the di ff erence is extremely small so we
can without loosing accuracy, neglect that).
Thus, depending on your equipment at home, you can choose between either using
the ”
weight method ” or the ” volume method ”. If you do not have lab-equipment
concerning measuring volume, like a ” volumetric flask ”, or a ” graduated cylinder ” of
at least 500ml,
we recommend user in first place go for the ”weight method”
,
and using a reasonable good kitchen scale, with resolution of 1g, and at least a max
capacity of 2500-3000g. That method will, if following our instructions very carefully,
give an accuracy of the ready to use solution by 0.2% or better. That have
absolutely no impact at all of the final measurements.
The volume method, with a lab-grade volumetric flask, can give an accuracy of the
ready to use solution by 0.1% in best case. There is no need to chase numbers in
this field, so 0.2% is absolutely fine, and will not be seen in the measurements.
Weight method
Most users will find this method the best and most straight forward, and is
recommended if you do not have lab-grade volume measuring items.
The only thing you need is a kitchen scale of reasonable quality with a resolution by
1g, and preferably a maximum weight capacity of at least 2500-3000g.
It is advisable to not mix too much at each occasion. We recommend mixing a
maximum of 2500-3000 g each time. That will last around 8-9 weeks in normal
usage. If you mix larger quantity each time, and maybe do some slight error, you will
regret that.
The advantage with this method is that you perform the whole procedure by one
single weighting
, and in that way reduce errors.
As the specific gravity of our reagent is 1.00g/ml we can still use the 1/4 relationship
between the weight of the reagent and RO water.
Practical procedure:
In this
example
you wants to make
2000ml of a ready to use solution
:
• Place a canister (please make sure it is completely clean and only are used for
this purpose from start) on the scale.
• Press ”tare” on the scale to make the readings to 0.00 g
• Now carefully fill upp with reagent to the readings of exact 400g.
• DO NOT remove the canister from the scale, let it be, still reading 400 g of
course, and now add RO-water until you read
exact 2000 g at the scale. Done!
Advice:! It is maybe not easy to hit the weight targets exact, so when you are
quite near the target value, use a pipett or syringe (never used before) or
similar to add the last reagent/water very precise!
Plastic pipette or syringe ( use
it only ones, and use new and completely clean ) are easy to get from
pharmaceutical shop or aquarium shop.