10
* 1 FTU = 1 NTU
• Even though HI 93703
covers a very wide range of turbidity
values, for very accurate measurements of samples exceeding
40 FTU*, Standard Methods require dilution. In such cases,
the correct amount of HI 93703-0
or turbidity-free water to
be added to the sample can be calculated as follows:
Vos = 3000 / T
where: Vos= volume of sample (mL) to be combined with
HI 93703-0 to obtain the final volume of 100 mL.
T=HI 93703 reading (exceeding 40 FTU*)
E.g.: HI 93703 reading = 200 FTU *
3000 / 200 = 15 mL (Vos)
15 mL (Vos)+85 mL (HI 93703-0) = 100 mL
At this point, take a sample of this solution and measure turbidity.
The correct turbidity value of the original sample will be:
T
n
x 100 mL / Vos = T
a
where: T
n
= new HI 93703 reading
T
a
= actual turbidity value of the original sample
E.g. If T
n
= 27 FTU *
T
a
= 27 FTU *x100 mL / 15 mL = 180 FTU *