Everything that is in your solution counts toward your target PPM. That's why it's your target. A target isn't something that you try to achieve, but it's OK if you go over by 30%. No, you actually want to try and achieve your target. That includes additives, nutrients, whatever comes out of your tap, fly poop, etc. Your tap water may contain desirable nutrients, especially if it's well water. Copper, iron, zinc, all sorts of crap that the plant can use, and some of which it actually needs. You've gotta count this stuff.
Opie Yutts Reviewed by Opie Yutts on . Base PPM and Nutes Something I haven't been able to figure out is... Lets say PPM of tap water is 200, vs RO water which could be 50... if wanted my PPM to be 400 for my reservoir, and Im using tap water with a base of 200 already, Then I would only be able to put as much nutrients in to make it 400, right? But if i was using water if a base of 50 PPM, then I would have 150 extra PPM of nutrients? So does it slow down growth by using water with a high base PPM since you can't add as much nutrients? or Rating: 5