In addition to the previous ...
Published by Mark Beatty, Employee at Utility Technologies, LLC
In addition to the previous answers:
1. Make sure to have a good ground with either grounding rings, or a grounding electrode.
2. Most mag meters require about 3ft/sec flow rate to be accurate. You can increase the flow rate by downsizing on size to get the flow rate up. If downsizing, the the reducer must be concentric.
3. The fluid measured must be electromagnetically conductive. For example water from a reverse osmosis system cannot be measured since deionized.