Here's what google says about PPMs and water quality
Drinking water from reverse osmosis, distillation,,, etc..0-50 PPM
Often considered acceptable range for carbon filtration, mountain springs or aquifers. 50-140 PPM
Average tap water. 140-400 PPM
Hard water. 170 PPM or above
Less desirable 200-300 PPM
Unpleasant levels from tap water, aquifers or mountain springs. 300-500 PPM
The EPA's maximum contamination level. 500 PPM
Is your meter made in china? Is it yellow? Do you adjust it with a screwdriver?
If the answer to these are yes, i'd look into another meter!