Question regarding TDS

A question from a fellow grower:

Regarding TDS, you mention that 100 to 150 is desired, yet when I measured rainwater coming off my roof it was 16 and the rainwater coming from the sky was 3. Plants seem to love rainwater, so my question is why does rainwater seem to work so well at 3 TDS, when the desired TDS is 100-150? Thanks, Lee

More information could be needed.

Who mentions 100-150 PPM is desired?

Rain water should be pretty close to zero as it is basically distilled water.

Rainwater or zero PPM water is great to water your plants with, or to use to mix your nutrients into.

Thanks for input MG Stoner! Robert Bergman (in his last promo email) suggested 100-150. The guys at Supercloset ran a free video course a few months ago and suggested about 50 TDS. The rain from our last rainstorm produced 2 TDS, The water from my tap is about 259 TDS and when I used a whole house water filter from Lowes, the general vitality (not TDS) of the water was about 100. When I removed the water filter, the general vitality of the clorinated water increased to about 170 (higher is better). After leaving the water out for 24 hours, the general vitality of the de-clorinated water was about 230. When I tested the rainwater, the general vitality was 360. Since I am developing a quantum fertilizer, it appears my testing will allow greater control if I use rainwater or distilled water.