You still aren't giving all that precise information, like, I have no idea what your pH is for example... but how do you take apart and clean the system, and when was the last time you did it?
Also your tap water is WAY too hard to be running a standard hydro nute on. You are going to need to switch to 'hard water formula' or RO supplemented with calmag.
What is your reservoir temperature by the way?

I posted that form so you could copy it into your relpy.