I shocked my tub today and left the cover off for awhile and when I went back to close the cover, I saw a bug floating on the surface so stuck my hand in right underneath it and felt a very mild static discharge type of shock. I have not ever felt static before on the water but it has me somewhat alarmed.

I stuck both probes of my multimeter into the water and am registering a slight voltage. 0.03v but depending on how far my probes were from each other, I did see it climb to about 0.21v.

Am I going about testing this the right way or should I have one probe in the water and other touching ground?

I’ve put my hand in since and have not got any static shock but the first time was after it sat for 3 days unused so may have built up. Any ideas or suggestions for next steps would be appreciated.