i am 5 weeks into flower , greenhouse glh seeds, e&f, when i was in veg my nutes will drift from 5.5 to 6.0 in a couple of days. for the past 2 weeks my nutes are drifting down from 5.8 to 5.5 the same as above but down drift is this normal, using ff nutes just added cal mag a week ago some fan...