Hi people,I have 2x 8 pot wilma systems and my plants are 3 weeks 12/12 has anyone had exp or knows if i really need a nute change,the tanks are 80L and im adding at least 15L of fresh nute a day 105L a week ec is pretty stable 1.8-2.1 ph 5.8,dont want to throw nutes away if not needed some say...