Funny you should mention ppm, because I just picked up a soil meter. B4 I was just testing the runoff with a liquid tester. I wanted to get something more accurate. The problem is that I really don't understand the ppm part. Also if your ph is to high or low, how do you add lime to a plant soil? This is the part that intimidates me a little. But my friend grows and he's an idiot so I'm sure I would respond well to any guidance.
PPM. Parts per million. In a general sense it means to dilute.
Rosey was correct, I use ph-up/down for my water or when I use nutes, which is very rare for me. I usually grow with ph'd water and that is it. Whatever the soil has in it, is what my plants get.. I'll usually add a food with high (N) content during flower to keep things green instead of getting the yellowing that so many believe is natural during that process. (it isn't natural for leaves to just turn yellow and die) Green leaves = healthy plant.
Raising soil pH: (to make it more alkaline)
It is generally easier to make soil mixes more alkaline than it is to make them more acidic. The addition of dolomite lime, hardwood ash, bone meal, crushed marble, or crushed oyster shells will help to raise the soil pH."
Lowering soil pH: (to make it more acidic)
If your soil needs to be more acidic, sawdust, composted leaves, wood chips, cottonseed meal, leaf mold and especially peat moss, will lower the soil pH.
There isn't one fix for everything. Most of us experience some sort of deficiency at one point or another. It doesn't matter how long you have grown cause not all plants will react a certain way to your medium.
Hope this helps.
Some sprinkle the lime on top and water, others mix it in water and add it that way. I think he uses pH up/down kit 
