One other thing I talked to the salesman about. I've noticed that most locals who get these things donated to them don't clean them enough so they clog up and stop using them. I've had friends with restaurants get them and cleaned them and refilled them myself when I see they need it. They're too much trouble. New habits hard to take on if it means going to more trouble than the old ones. Even poor people will buy water or boil water (which doesn't get the pesticides) rather than get into using them right. We know a guy who gets grants to to distribute them all over to the poor and refugees from volcanoes and earthquakes. He does one quick mass instructive talk and is off. Good luck. I suggest the company do a followup. Potable water from the tap is far superior. There are also many places with potable and non potable supplies running next to each other.
If you got heavy metals in your water you have to move up to a more sophisticated system.