Here is how I built my spray injector for foam generation for my protein skimmer In my tests this generates more foam than a Kent Turbo 3/4″ venturi.
The key to this is the nozzle design. I drilled 8 x 3/32″ holes in a 1/2″ MPT PVC plug.
After running for 3 months this nozzle is clean as a whistle. It did however clog once after I removed the prefilter on the MAG 5 I had running it. A small chromis got sucked in diced and did successfully clog all the nozzles. So always run with a prefilter or pump inlet guard of some type.