So I know there are a lot of RO system enthusiasts who swear by it for their hydroponic watering systems. Given that I only grow roughly 2-3 plants in my tent… plus with my tap PPMs being considerably good (Around 65-70ish) I didn’t feel it was necessary to invest in the system
If you need further evidence of that… review my previous grow. All done with said tap water 
That being said, I switched over to distilled water due to issues earlier with keeping the res water as gunk free as possible. Since distilled water is pricy ($2-3 per gallon), I purchased a Vevor distilled water making system = https://a.co/d/8UemkDE
Granted it’s a bit more work (Takes roughly 3-4 hours to brew a gallon of water), but it works pretty well getting most of the minerals out of your water. These are my readings using the same tap water I just mentioned earlier -
