yeahhhh you need a PH meter

it will make things way easier, as far as MAKING SURE your plants are getting the nutes
at the wrong pH.. certain nutrients are locked out.. so if your pH is wrong your basically choking your plant, and trying to feed it at the same time
optimal pH = optimal nutrient uptake = optimal plant health
$45 bucks, and you can replace the sensor.. I'm likin' that