PH meter question

High All,
I have 2 PH meters (an EcoTest and a Hanna), and both do the same thing: I put them into a nutrient solutions that I want to test, and, in a minute or so, they stabilize with a reading. However, if I then swirl the end of the meter in the solution, the reading changes, sometimes a lot. It will go from a reading of 6.0 to 5.1 -- enough that the difference would hurt my plants. So, which reading is correct? I've emailed both Hanna and EcoTest and no response, so if anyone knows what's going on here, I would appreciate some guidance.
Thanx, Bob in Arizona

You might be creating a pressure and temperature difference between the inner and outer portion of the membrane. You are introducing noise in to the measurement when you swirl with the probe. What models of meters are you using? Hard to speculate too much without knowing what types and features the meters have. What kind of membrane, electrode, etc. Does your meter have an automagic temperature correction feature? Has it been stored sterile in the proper storage solution? Have you calibrated it with reference buffers? Sorry your question went unanswered. I don't have familiarity with EcoTest, but have worked with many Hanna benchtop units and Hach portables. Sorry I can't answer without more info.

I swirl the meter but then stop to take the reading. Too many people are trying to get pH too close to an ideal. A variance of .5 should be of little concern.

This is interesting. I use the drops because of all the things that can go wrong with the ph pens im a clutz id rather spill than break something. how do I sub to a thread?I want to hear feed back on this issue