Not easily. I don't have a kit and the LFS doesn't test for it.
KH2PO4 dosing is the standard EI amount, as was the KNO3 which has proven to be massively overdosed. That doesn't completely rule out a P deficiency of course.
I'm seeing dust algae in several spots in the tank now, plus some BBA on the glass. Time to compensate for the CO2 being lost to the ripples from the new spray bar.