Buffers vs pH adjusters?
So I know buffers have an acid and a conjugate base, whereas the adjusters (such as "pH up") only have single compound. This is why you can use neutral regulator (or API's similar products) to both raise and lower pH to 7, but a pH adjuster only goes one way.
If you are starting with a very low (or high) pH, such as 4.5, would it be a better idea to first use an adjuster to get it close to 7, and then add the buffer to keep it there, as opposed to just dumping in neutral regulator until it eventually gets there. I would imagine that if you use a buffer to correct pH over a large range (4 up to 7), there will be a whole lot of unused chemicals in the water in the form of the unused acid/base pair.
Furthermore, would it matter if the adjuster was carbonate and the buffer was phosphate? and why