YSI 9300 Photometer - Manual (Page 34)

Test Instructions
1 Fill test tube with sample to the 10 ml mark.
2 Add one Ammonia No 1 tablet and one Ammonia No 2 tablet, crush and mix
to dissolve.
3 Stand for 10 minutes to allow color development.
4 Select Phot 4 on photometer to measure Ammonia mg/l N or select Phot 62
on photometer to measure ammonium mg/l NH
4
.
5 Take photometer reading in usual manner (see photometer instructions).
Sea Water Samples
YSI Ammonia Conditioning Reagent is required when testing sea water or
brackish water samples to prevent precipitation of salts. The reagent is supplied
in a special ‘spoon pack’ to aid measuring out the powder.
Fill the test tube with sample to the 10 ml mark, and add one level spoonful of
conditioning reagent. Mix to dissolve reagent then continue the test as described
in the above test instructions. If turbidity still forms in the test, repeat using two
level spoonfuls of conditioning reagent.
Notes
1 At low temperatures the rate of color development in the test may be slower.
If the sample temperature is below 20°C allow 15 minutes for the color to
develop.
2 Ammonia concentrations can be expressed in a number of different ways.
The following factors may be used for the conversion of readings :-
To convert from N to NH
4
multiply by 1.3.
To convert from N to NH
3
multiply by 1.2.
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