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2pH devices...2pH values reading (..long..(:...)
Hi All.
I have an pinpoint pH probe attached to a Neptune controller.This pH device
works for more than 1 year.
Few weeks ago I bought a pHep device from Hanna.
When I use to read the pH parameter I always had different values.
I made several calibrations with both probes, many test..but same result.
here some of readings on different water parameter.
First, I did calibrate BOTH devices with brand new calibration solutions at
both values 4 and 7.
Then I took water samples in an clean recipient, so I could avoid any other
sources of electrical or whatever could affect the reading.
Water source pHep Pinpoint TDS KH test kit
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Planted tank 7,3 6.86 200ppm 70ppm
Breeding tank 6.4 5.77 80ppm 20ppm
Osmosis water 5,8 5,06 <10ppm <17ppm
Notes.
TDS (total dissolved salts)is an electronic reading device from Hanna
KH test kit is Aquarium Pharmaceuticals.
The pHep device is new. To be able to read the pH value I do have to wait
about 3-4 minutes so the probe should show the value w/o any changes.The
pinpoint device (1 year old) does stabilise in max 2 minutes.
Both devices does calibrate OK and remain that way.
The reading differences are only when I need to test the water pH.
I do know that the pH probes do get old and they go off one day...So,
logical the pHep device should read OK and my old pinpoint has gone
crazy.........But as the readings I do think the old probe is more accurate.
Any suggestion are welcomed.
I am very confused about this matter.
Cristian