Rain water TDS is

[northbay-reefer]

Zero

have anyone use rain water for make up water ?

[sulcata1619]

That's suprising that it is zero. i thought there would be all kinds of crap in it with the amount of co2 gases in the air. AHHH acid rain.

[northbay-reefer]

Well I would run it through some carbon filter before using it, but I think its totally worth while to give it a try

[gdm42001]

Although it reads zero, I would still be concerned with it pulling pollutants and such out of the air on the way down.
Rainwater is as much as 100 times softer than well water, with lower mineral content and total suspended solids.
It might also be a good idea to run it through a UV Filter.
How would you collect it? off the roof?