PH probe reading low.

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lartho6
Posts: 35
Joined: Wed Oct 24, 2012 7:33 am

PH probe reading low.

Post by 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
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: PH probe reading low.

Post by rimai »

Those numbers don't look right?
What color of pH probe do you have?
Roberto.
lartho6
Posts: 35
Joined: Wed Oct 24, 2012 7:33 am

Re: PH probe reading low.

Post by lartho6 »

blue..
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: PH probe reading low.

Post by rimai »

What kind of reading do you get when you place the probe into a cup with tank water ?
Roberto.
lartho6
Posts: 35
Joined: Wed Oct 24, 2012 7:33 am

Re: PH probe reading low.

Post by lartho6 »

i used distilled water and i got a reading 280 ish...
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: PH probe reading low.

Post by rimai »

Distilled water is too pure.
You can't get correct ph readings. Read the article about pH from Randy. Very interesting read.
Roberto.
lartho6
Posts: 35
Joined: Wed Oct 24, 2012 7:33 am

Re: PH probe reading low.

Post by lartho6 »

didnt know it is a neat article i guess i should redo that memory ?
rossbryant1956
Posts: 471
Joined: Sat Jan 14, 2012 2:08 pm
Location: Montgomery Village, MD

Re: PH probe reading low.

Post by rossbryant1956 »

please send us the link to the article from Randy on low ph readings. Thx
Roscoe's Reefs - Starting Over Again:

Building new 29g Nano after landlord went berserk over my 4 75 gallon tanks, Multiple RA's, Water mixing stations, etc. Your help welcomed in remembering all I've forgotten.
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: PH probe reading low.

Post by 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.
Roberto.
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