This is quite simple maths :
Dealing with a 80% grade sodium chlorite powder starter, making a 28%(w) MMS solution means 28%(w) + 72%(w) water (distilled) to make the 100% MMS solution. The (w) specify that we are dealing with a weight %. At on point I will stop writing it but it is always implied.
So : 28 g SC + 72 g water = 100% of our 28%(w) MMS solution.
The beauty with the metric system is that with pure water, by definition, volume = weight
x ml = x cc = x g
thus our 28%(w) MMS solution =
28 g SC + 72 ml water
leading to : if 72 ml of water needs 28 g of SC, how much SC is needed for 1 liter ?
72 ml = 28 g
1000 ml = ?
? = 1000 x 28/72
? =389 g
or 390 g
giving that a MMS solution have a
390 g/l
(grams per liter) concentration. If you would have prefered to round up to
400 g/l
, this would be fine since it would produce a slightly overconcentrated MMS solution of 28.57%, an overconcentration of 2% that is quite acceptable.
But since we deal with a 80% grade SC, the real SC concentration is 390 X .8 = 312 g into 1390 g of solution, giving a real 22.44%(w) SC MMS solution.
If we deal with the 400 g/l figure, this would give 400 x .8 = 320 g of real SC into a total of 1400 g solution, thus a real 22.85%(w) SC MMS solution, giving a real 1.8% overconcentrate SC MMS solution. A very acceptable error margin.
Another very useful figure to use when making MMS solutions woud be what I call the
Magical
Multiplicator
Ratio
MMR
that is 1000 / 390 or
2.56
,
or if you deal
with the 400 g/l figure, 1000 / 400 =
2.5
.
Why this
MMR ratio is usefull ? Let say you have 555 g remaining of SC powder, in what volume of water do you have to mix it in to produce your MMS solution ?
answer :
555 x MMR
555 x 2.5
1387.5 ml
since with
MMR = 2.5, we have a slightly 1.8% overconcentrated MMS solution, this allows us to round up upward the result, here 1387.5 ml to :
1400 ml
giving a 28.3%(w) MMS solution.
Inversly, how many grams of SC do I have to use to make a 300 ml solution ?
answer :
300 ÷ MMR
300 ÷ 2.5
120 g
To sum up :
if we have
X ml of water and want to know the
Y g of SC to use:
Y g = X ml x MMR
if we have
Y g of sodium chlorite and want to know how much ml of water to use:
X ml = Y g ÷ MMR
MMR = 2.5
---- ---- ---- ---- ---- ---- ---- ---- ---- ----
Now, if we want to deal with another grade (concentration) of sodium chlorite powder (liquid), we have to make the following adjustments :
The 390 g/l figure (or 400 g/l), is for 80% grade SC. If we use, per instance, a 40% grade SC, we would need not 390 g but twice that amount of SC to achieve the wanted MMS solution concentration. Thus, we have to multiply 390 by the grade ratios, or 80/40 !
So, the
C concentration needed for a known
Z new grade (concentration) woulde be :
C g/l = 390 x 80/Z
and your new MMR would be :
MMR = 1000 / C
Dont forget that this is also valid for liquid sodium chlorite as long as you deal with it by weight, not volume. Only water can be dealt with by volume.
LOL
iBenny