Weirs and tennis balls

MikeInTN

TFP Expert
LifeTime Supporter
May 27, 2007
1,335
Middle Tennessee
When I had my pool installed a couple years back, the installer didn't put the weir in the skimmer. It wasn't really needed per se because the pool store I bought the pool from recommended leaving the pump running 24x7. They also recommended leaving a tennis ball in the skimmer to break up the vortex that forms from the pump intake so that the pump wouldn't start sucking air. I decided this year to put my pump on a timer, and found out fairly quickly that I needed my weir in my skimmer to keep all of the Crud in the skimmer basket from floating back out into the pool when the pump kicks off; however, I've noticed that the tennis ball sometimes gets underneath the weir when the pump's running. So, do I still need the tennis ball to break up the vortex, or will the water flow over the weir do that for me??

TIA,
Mike
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
If the water level is high enough there shouldn't be enough of a vortex to draw any air and you won't need the tennis ball at all. For my skimmer I only need the water to be one inch above the opening and everything is fine. That still leaves me several inches of water level variation between there and the top of the skimmer.
 

Poolsean

TFP Expert
Apr 15, 2007
1,462
Ft Lauderdale, Florida
Mike,

The skimmer weir door is necessary, as it actually increases the suction from the pool into the skimmer, and as you found out, it keeps the debris in the skimmer box.
You may want to try adjusting the valve between the skimmer and main drain to avoid the vortex and by all means, get rid of the tennis ball.
 

MikeInTN

TFP Expert
LifeTime Supporter
May 27, 2007
1,335
Middle Tennessee
I'll try removing the tennis ball tonight and see what happens. In the past, I've had to keep the water level about an inch or so below the top of the skimmer, but that was also with the 2HP pump. Unfortunately, I don't have a ball valve between my skimmer and the pump (yet) so I can't adjust water flow that way. I usually cut the water flow off from the skimmer by plugging it with a rubber plug.

Thanks guys!
 

matt4x4

Well-known member
Apr 2, 2007
312
skimmers

The vortex does work in conjunction with water level, each skimmer/pump combination will have it's own happy water level where the vortex disappears, if a pump draws higher GPM's the water level will need to be higher to avoid the vortex.
The weir is nice to have not only because it keeps Crud in the skimmer, but it also aids in pulling more Crud into the skimmer.
Remove the weir and you will see your water level rise in the skimmer, things really close (2") to the wall will start to flow right past the skimmer because there is no draw into the skimmer. add the weir, it acts like a set of rapids and water starts to flow faster and downhill into the skimmer because the partial blockage by the weir creates a lower water level in the skimmer compared to the pool, this in turn will draw water from further out in the pool outside of the skimmer, effectively grabbing the Crud that flows along within 6 inches of the wall and sucking it into the skimmer.
 

NWMNMom

TFP Expert
LifeTime Supporter
Apr 8, 2007
1,582
Waaay NW MN
Oh good explanation Matt! All I know is if it wasn't for that weir each time I vac, Crud would backflow when the pump is shut off. I keep my water level at about 1" below top of skimmer opening - but I guess I did notice the thing about the stuff getting channeled into the skimmer.