I'm not sure if this was the place to ask this as it has to do with both doctoral smarts and science smarts.
Some guy came over to my house to test our water clarity today, and he hooked some device up to 3 different glasses of water. (i think he called it some kind of electrode device? I missed that part)
one with tap-water, one with the bottled water we drink, and one with the water he brought.
After using this device, the tapwater became litterally black, it looks like a bunch of broken up pieces of dirt, or crap.
The bottled water turned with a little bit of orange sand at the bottom, and his water had nothing out of the ordinary.
This guy wants to charge us some monthly fee for a filter, which is tempting considering what we saw in the water weve been drinking...
What i'm asking is if this guy is a con, and if what he showed us was some form of trick, ive heard and I know alot of con bull crap, but I cant pinpoint this one.
Any help or comments are appreciated
thanks