Hey dramboui,
Well, usually soil has a pre-adjusted ph if you bought it from a gardening store. Water is naturally around 6.4-7.0, and you don't want to add nutes when your plants are babies. Do you have your plants going already? You want your soil ph to be around 6.3-6.8, so adding nutrients without having to "adjust" it is alright. You don't want to adjust any ph's in soil if your plants are growing well. Only when you start having a problem do you want to deal with what ph your soil is at. What kinda nutrients are you using? Give as much info as possible. What is the ph of your soil? How old are your plant? What kinda soil?