Hey guys a week ago I noticed yellow spots on lower leaves on one plant and brown spots on lower leaves on other plant and now the brown spot ones leaves are dead and the yellow spot plant has the yellowing spreading. First time grower and have no clue what's going on. Been watering with 6.5ph and green planet hydro grow a/b every other watering. 5ml a/b last watering so 10ml total per gallon. Please help me I'm really worried now.