I did a Google search for white peat. Here is what I found.
White peat is newer, less decomposed peat, found on the top of older, more decomposed black peat. It has fewer nutrients ready for the plant to use than fully-decomposed peat.
White peat is courser than black peat, and thus adds more porosity to the soil. The sites I visited spoke only of mushroom farms, large agricultural or outdoor garden applications, not indoor grows in relatively small pots. The mushroom site said that the use of white peat is a substitute for adding perlite, as it is hydrophobic (sheds water).
You can try it in varying contraventions in several pots and compare the differences in water retention and plant growth.