We are trying to set up a phagocytosis experiment using the pHrodo Red E.coli Bioparticles, but we can't see any phagocytosis after different times of incubation.
I haven't worked with the red but have worked with the green. Always had great success with that kit.
Are you following the complete protocol, or have you made any changes? Transporting blood in heparin tubes (NOT EDTA) and at room temperature is best. Make sure you fill the tubes completely (though heparin tubes even half full should still have great results).