PR-10,000 works well with chlorine, and while it impacts ORP indirectly, the ORP probe may be tricked temporarily.
PR-10,000 can indirectly affect ORP, and only temporarily. It does not directly increase water's potential for electron transfer (which is what ORP measures), but it removes phosphates from water which helps prevent algae growth and therefore might reduce chlorine consumption. So it's an indirect relationship.
PR-10,000 has a strong electrical charge to it
Part of what makes PR-10,000 so effective in phosphate removal is its strong electrical charge. It attracts phosphates to it easily. But this charge can distort (or trick) an ORP probe too.
ORP and pH probes on a commercial pool
And it's odd because some customers tell us they used PR-10,000 and their ORP plummeted, while others tell us their ORP spiked. Most users don't mention it to us at all, because most users experience neither. If used correctly, PR-10,000 will react out in the water itself, and it has already precipitated inert phosphate dust before being pulled into the main drain. But if for some reason PR-10,000 is pulled into your circulation system and past the ORP probe, yes there can be interference.