russrahlanswered grow question 4 years ago If you have 400ppm going in and 1800 coming out there is definitely a buildup in your soil. I use city tap water for all my DWC buckets and have for decades with all my grows. Once I bought distilled water for an entire grow way back in the 90’s, had empty 4L jugs coming out my ass....lol didn’t really see a noticeable difference though. City water is clean, filtered, and usually pretty low ppm(my current tap water sits about 70ppm I believe). But if I were you I would flush her with proper ph tap water till you have basically the same ppm going in as out. This goes for ph as well. Hope this helps, Cheers💨