PH probe reading low.

[lartho6]

using the 7 solution it stabilized at 318 and using the 10 solution it stabilized at 597, which its giving me a sump reading of 5.00 what did i do wrong.

[rimai]

Those numbers don't look right?
What color of pH probe do you have?

[lartho6]

blue..

[rimai]

What kind of reading do you get when you place the probe into a cup with tank water ?

[lartho6]

i used distilled water and i got a reading 280 ish...

[rimai]

Distilled water is too pure.
You can't get correct ph readings. Read the article about pH from Randy. Very interesting read.

[lartho6]

didnt know it is a neat article i guess i should redo that memory ?

[rossbryant1956]

please send us the link to the article from Randy on low ph readings. Thx

[rimai]

http://reefkeeping.com/issues/2004-09/rhf/index.php
http://reefkeeping.com/issues/2005-05/rhf/index.php
The second one is the one he mentions about pure water.

The pH of highly purified water is not accurately measured by test kits, or by pH meters. There are several different reasons for this, including the fact that highly purified water has very little buffering capacity, so its pH is easily changed. Even the acidity or basicity of a pH test kit’s indicator dye is enough to alter pure water’s measured pH. As for pH meters, the probes themselves do not function well in the very low ionic strength of pure freshwater, and trace impurities on them can swing the pH around quite a bit.