I purchase two of the venturi eyeballs when I retrofitted my Intex pool with a "real" skimmer return. I have two of these, one at the "normal" Intex location and another, lower, about the same height as the Intex round return.
Having an Intex setup I feared the pump would not "flow" enough water to get good venturi action so I used a Dremel to expand the inner part of the Venturi return to exactly what the plastic molding was. So, yes I feel I get more flow and after first starting the pump, boy did I ever get great venturi action from these eyeballs. With hard plumbing and an Intex 2650 filter pump I don't have a whirlpool, but you can float round the pool in a blowup doughnut in about a minute and a half due to the movement of the water.
If I had a real hayward or Pentair pump on this pool, I know I would not have needed to dremel out the eyeball inner piece. I had wanted these to mainly move my water better than a regular eyeball to better distribute heated water around the pool. Last year, the further away from the returns you were, the cooler the pool was.......now, very little noticable temp difference around the pool. Mind you this is using the same heater as last year on a smaller pool with partial hard plumb.
Effectiveness for water movement cannot be understated with these eyeballs cannot be understated. Particularly with hard plumbed Intex pool. If/when I move to bigger pool or "real" AGP, I will use these for return. These things keep the water moving.....
Bob E.
