Just set-up 4040 RO, all working well and getting about 12 TDS pre DI can. Just had a check of rain water that collected in plastic container that was outside and it was reading.......8.2 !! Had a few more checks of other areas of rain water and showing about 8.
Is the exceptionally low for rain water and is it low because of bad weather ie air purier after storms etc.
If it is consistantly low as this wouldn't it be better to water harvest and pump water from raon water containers through DI into IBC ..avoid RO alltogether???