Observation

In part (a), majority of the candidates could not name the water quality measured by each of specimens C and D.

In part (b), majority of the candidates did not state the correct optimum range of water measured by specimens C and D.

In part (c), majority of the candidates could not describe how specimen C is used to take measurement in a fish pond.
In part (d), majority of the candidates could not mention three other water quality parameters that could be measured in a fish pond.

In part (e), majority of the candidates could not name three other items that could be used to measure water quality parameters in a fish pond.

The expected answers include:

1(a) C – Temperature
D - pH / acidity / alkaline

(b) C – Temperature:   24 - 320C
D -  pH            6.5 – 8.5

(c) -  Hold the tip of the thermometer at the upper end
-           Shake the thermometer ( to return the meniscus to zero)
-           Dip the mercury and of the thermometer into the pond water / partially submerge
-           Keep in the water for few seconds / some time
-           Bring out / withdraw the thermometer
-           Raise the thermometer to eye level
-           Take the reading of the lower meniscus
-           Repeat the process at several point in the pond
-           Find the average

(d)       -  Dissolved oxygen / DO
-           Turbidity / dissolved solids
-           Conductivity
-           Salinity
-           Ammonium (NH4)
-           Nitrous Oxide (NO)
-           Nitrite (NO2)
-           Nitrate (NO3)
-           Hardness
-           Transparency

(e) -        D.O meter
-           Litmus paper
-           Secchi disc
-           Conductivity meter
-           Turbid meter
-           Salinometer
-           Hach kit / water test kit