What is a Venturi Skimmer?

To begin, I want to give a bit of background information to help aid in the understanding of how a Venturi Skimmer works.  The Venturi Skimmer utilizes the natural phenomenon known as the “Venturi Effect.”  This phenomenon occurs when a fluid that is flowing through a pipe is forced through a narrow section.  The result is a decrease in pressure and an increase in velocity.  That is the best explanation without getting too technical.  It was named after the man who discovered it, an Italian Physicist named Giovanni Batista Venturi.  Now that that’s out of the way, let’s get into how it applies to swimming pool skimmers.
I have been in the swimming pool industry for almost ten years, and I have never seen a pool that is without a skimmer.  This is because a skimmer plays an important role in the pool cleaning process.  It is a part of the filtration system in which water is pulled from the pool by the pump, sent through the filter which removes fine particles of debris and other small things that you wouldn’t necessarily want in your swimming pool.
 Then, the water is either sent through the heater, or heat pump if you have one, and returned to the pool to start the cycle over again.  In addition to that, the skimmer strains the water passing through of all the larger debris that might be floating on the pool’s surface.  This includes leaves, sticks, grass clippings, fuzz, and the occasional frog, toad, newt, etc.  Without a skimmer, all of that stuff would remain floating around in the pool until it is physically removed by you, the pool’s owner.  A skimmer also allows for the sweeping of the pool.  Whether or not you have a pool, most people are familiar with the image of a typical “pool boy” with a long pole in his hand, cleaning the pool.  He is most likely sweeping the pool.  For that, he would take a long, specially designed hose and attach it to the port in the skimmer that is pulling the water to the pump.
The other end of that hose would be attached to a vac head which is also attached to the pole in his hand.  This allows him to effectively remove dirt and debris that has settled on the pool walls and floor without having to physically enter the water.  That is the basic skimmer function, and it requires the suction of the pump to do so.  With the Venturi Skimmer, however, it is a little different.
To begin, let’s look at a plumbing diagram.  You can see that it functions like a standard skimmer, because it draws water from the pool to the pump.  This process will remove the debris from the surface of the pool.
However, unlike a standard skimmer, some of the water coming back to the pool from the pump is sent back through the bottom of the skimmer through the narrower Venturi tube and back to the pool.  This action creates an additional cycle, bringing water in through the mouth of the skimmer and sending it directly back to the pool.  What this does is double the skimming power without increasing the amount of energy used.  In addition to that, another benefit of this type of skimmer is that you could actually shut the suction from the pump to the skimmer completely off.
 This would allow the full suction of the pump to go to the main drains, and because the water is being returned to the pool through the skimmer, the Venturi action would still take place allowing the skimmer to still effectively remove debris.  This would benefit an In-floor cleaning system that relies on the main drain to remove debris from the pool.  By having full suction to the main drain, it would maximize its cleaning ability, and you would still get the benefits of the skimmer removing debris from the surface.  On top of all that, this type of skimmer works very well with low flow, variable speed, or two speed pumps.  Regardless of what setting those pumps might be running on, the Venturi action would still allow for exceptional debris removal by the skimmer.
To see this type of skimmer in action, check out this link Venturi Youtube video, from there you can see other related videos.
You can also get more information specifically about Waterway’s Renegade Venturi Skimmer here Waterway Renegade Venturi Skimmer