Originally Posted by acrylic51
Just ran out to the garage and tried it and yes the vinyl can be drilled and the hole did stay open.....the hose though was roughly 3/4" ID, but would assume smaller line would work as well.....if you have a scrap piece try it first on that.....
Although probably no longer germane to the discussion, if one would want to punch/drill a hole in vinyl tubing, it could be augmented by a barbed fitting made for sprinkler/drip irrigation systems. It's the little fitting made for tapping into larger irrigation line and running the smaller, "Spaghetti" line from there.
Just an FYI . . .
BTW, recently completed a freshwater system/leak test on our tank and when satisfied everything was working properly, shut off the return pump and monitored what happened to check for a "power outage" situation. I don't have an anti-siphon hole in the return piping, but the outlets are very near the surface. The water in the sump went up a couple of inches, but that was all.