Just had my pool plastered today and I noticed the installers used the same return fittings for the vacuum suction line. It's one of those threaded fittings that is the right inside diameter for the vac-lock fitting. However, their fittings are inside slip connections into my 1/5" suction line so the flow through the pipe is reduced to what looks like 1" at the fitting.
Is this the right fitting? I was expecting something that wouldn't be restricted, but I'm not sure if it really matters. I need this answered before I give them the final payment tomorrow.