Milwaukee pH Meter - Help!

[Myka]

I have a handheld Milwaukee pH meter. I have calibrated it with the fluid. I've had it for a few months, and used it a few times. It says you should let it sit until the numbers quit changing, but the numbers will keep changing all day. It slowly loses 0.1, then another, then another. It doesn't go up and down, just down 0.1 at a time, and about 60 seconds in between or so. I let it sit all day once. My first reading was 8.1, and it fell to 6.1 over a couple hours. Wtf? Is this normal?

So...how long should I let it sit before I take the reading?

I'm just re-calibrating right now since I have to open a packet of the pH 7.0 as I notice the fluid in the cap has evaporated. I notice that at first the meter said 8.0, and it took about 60 secs for the meter to get to 7.0. After three minutes it's at 6.9, so I adjusted it to say 7.0.

[mark]

not normal, probe failing, battery ok?

I leave my probe in a container that reactor effluent drips into. When I turn the meter on, see the numbers bounce a bit but become steady after about 2 second. If I move my probe into the sump, it locks into the tanks pH in about 15 second with me not moving the probe around.

Using a Milwaukee meter, Aqua-digital probe.

[Myka]

Mine never bounces around. It hits a number, and slowly falls. I was thinking the probe might be dying...not sure about the battery.

If you put yours in a cup of saltwater outside the tank, and let it sit, when does it stop moving?

[curtisharrison]

just wondering what should my ph be at in reactor

[Myka]

Originally Posted by curtisharrison

just wondering what should my ph be at in reactor

You might want to start a new thread, you will get more replies that way.

[fencer]

Just change the KCL in the electrode...that should fix it. If it doesn't then probe membrane is shot

[Myka]

Originally Posted by fencer

Just change the KCL in the electrode...that should fix it. If it doesn't then probe membrane is shot

KCL? Potassium chloride? lol I have no idea what that is. How do I do that? I'll try a Google search...

[fkshiu]

Most likely the probe is shot if it keeps drifting after recalibration. For the Milwaukee unit buying a new probe ($50 according to J&L) is almost as much as buying a brand new pH meter ($62).

The next pH meter I get will one with a probe which you can replace with a standard generic pH probe with a BNC connection (you can find them for about $20-$25) when it dies.

[Myka]

Ya, I contacted J&L about replacing the tip. Not worth it. I will probably just end up buying a Pinpoint pH monitor.

[fencer]

Potassium Chloride is the solution they use inside the electrodes.