Milwaukee monitor ???

[skhle]

I have 2 Milwaukee PH monitors SMS 122 & 120 for about almost ayear, how offen do you replace the probe (MA 911), I calibration a bout every couple months. Today I did some tests and it show some ?????.
First I calibrate in Pinpoint PH solution at 7.0 then I rinse in RODI water then put the probes in the sump, the probe of SMS 120 show 8.0, SMS 122 show 7.7 then I switch the probes to the other, SMS 120 show 8.9, SMS 122 show 6.9 .???????
So now I switch the probes back to their original monitors with them still in the sump, show SMS 120 ph of 8.0 ; SMS 120 Ph of 7.7. took probes out of sump rince with RODI water, put them back in Pinpoint solution they both show 7.0
Oh the probes stay about 3-5 min. in sump & solutiion.

Do both of monitors should read same when they are in same liquid ?, does any one ever done this ?

 

[DrBDC]

Did you only calibrate it with one solution or did you use 10 also? It needs a reference solution at a different pH in order to set the curve. When you switched probes you would have had to recalibrate that specific probe with that specific unit too.

 

[stlsaltwater]

most probes only last about a year or so ,before gettin wacky.

I use a pinpoint and need to replace ever year or so.....

 

[skhle]

DrBDC, I only calibrate with solution 7, my through was same brand probes, in same solution would give same reading in specialy same brand monitors, ......digital, sinals, 1 + 1 = 2 ???

And so probes needed replacement in about ayear ?.

 

[TWINPEAKS]

you should replace the probes when they can no longer be calibrated ie. when you have to turn the cali. pot all the way up or down.The pot should have some adj. in either direction when your done.I have had my milwaukee probe going on 2 years and it still cali. fine.You should cali. the probe in the solution that falls in the range you are checking.Saltwater #7 solution and #10 solution.

 

[skhle]

Thanks guys will do.

 

[McBeck]

One more suggestion - at our recent meeting Dwayne Lowry suggested leaving the probe in solution for 24 hours to let it stabilize. It's worth a shot before spending the $$ on a new one.