School me on coolant

[Brock]

I've seen it talked about here and there buy a couple people. Checking your ph level in the coolant, seen rawze talk about adding a additive to replenish. So let's learn what some of you do....

What do you use to test?
What levels are normal?
That's the ph levels, do you test for silica breakdown?

A radiator shop once told me silica was the most important thing......

Also does anyone have knowledge of cummins selection of coolants? Boy they have alot of types.

Thanks