Rain Water or Tap Water?

any info fellow growers ?

I use tap water and a dechlorinator. I run hydro

I always use rainwater when available, if I have to use tap water it is left in a barrel overnight with an aerator running to help the chloramines dissipate a little quicker.


Rain water on my outside and well-tap on my inside


Part of that decision depends on your tap water. If it’s just chlorinated with a decent ppm you can work around any shortcomings and be happy. Chloramine would add complexity.
Rain water and r/o are basically stripped of everything. If you want complete control of everything it’s a good way to go. Be forewarned, you’ll have to be sure to add supplements throughout your grow.
I use my municiple water. It’s got a pH of 7-7.3, ppms around 80-90, and I let it sit out for 24-48 hours to dissipate then chlorine. I adjust with fresh lemon juice and have been very happy with the results.



Make sure you add calcium and magnesium to rain water or RO. Tap water usually has plenty, otherwise get some CalMag. Unless your nute solution is designed for RO and includes calcium and magnesium.