Your using the meter for your nutes before you feed the plants, that way you know how much your giving them. There's nothing wrong with Advanced Nutrients as stated but you should get a feeding schedule and carefully read it. A PPM will save you tons of problems until you get it down pat and don't need the meter anymore.Ill get one today, I thought a PPM meter wasnt needed in soil grows, im adding the right nutes per gallon, PH levels are right, lighting, temp humidity is all where it should be.