[organicaf]

You could... detect pressure build up -> assume clogged

set pressure 0

open a solenoid connected to h2o2 with enough elevation to reach the clog

detect flow increase ->assume unclogged

close solenoid, set pressure 50 psi (or whatever)

This might best be done with a hydraulic circuit rather than electronic sensors, by the way. Ie. to detect pressure build up have a secondary line with slight resistance before the nozzle that when pressurized triggers other hydraulic elements which cut pressure, etc.