You could if you really wanted to, but they will mix.
IMO it looks pretty bad, a black and white (or almost white) mix like that. To me, it does not look very natural.
If there is any way you can use all EC, that would look better.
I used EC and Soil Master Select, charcoal. That blended well. Unfortunately SMS is not on the market any more, and the similar products are not available in that color.
Pool filter sand is OK in an aquarium. It has no cationic exchange capacity, so is not one of the better plant substrates, but is cheap and easy to use. Minimal rinsing, no chemical effects (no ammonia cycle, reduction of carbonates & pH, or anything else).
The color of the locally available PFS is OK. Sort of off-white with some darker specks here and there. Sort of like a beach.