Focustronic Alkatronic, Руководство пользователя

Страница: 28 / 39

28
Trouble shooting
Bad accuracy
Defines as more than 0.2dKH di ff erence from the
known
dKH.
• First of all, make sure that you really know the ”correct” dKH. That is not easy, as
even a brand new manual KH test from the market, mostly have an inbuilt
inaccuracy of around 0.2-0.3dKH! Most manual dKH tests measure too
high, as it is di
ffi cult to judge the proper color shift of these tests and the
reagent due to its small volume is fast contaminated/diluted. If you for
instance find that Alkatronic measures constant 0.2dKH below a manual
test, and you have done the checklist below, it is most likely that you have
no inaccuracy from Alkatronic at all!
•
Check pump calibration status for Pump A and C, by using the ” Test pump
accuracy ” function (see above). If the volume of the delivered fluid isn´t within
the ranges below, redo the calibration of that pump.
• Pump A:49.5-50.5 ml
• Pump C:9.9-10.1 ml
• Make sure you were reading the measure cylinders correct when you
calibrated! See page 12.
• Check pH electrode by using the ”t est pH -electrode ” function (se above) and if
the reading is deviating more than 0.1 pH from the reference fluid, redo the pH
calibration.
•
Make sure that the pipes are in correct positions! The pipe from pump B must
be in contact with bottom and the pipe from pump A must be around 2 mm
above botton,
and the pipe from pump C should be around 20 mm above
surface level when measurement vial is in standby mode (containing 50.0 ml).
• If you have excluded incorrect calibrated pumps and electrode by procedure
above, and you are 100% sure about the true dKH, then it is only one
explanation left: Slight inaccuracy of the reagent.
In that case you have probably
not been careful enough when mixing the reagent. If that is the cause, please
consider using the ”
Baseline calibration ”, see page 23.
Bad precision
Defines as more than 0.1dKH variance between 2 measurements of the exact same
water (thus not biologically active water).