Little Giant = Little Flow

[seamonkey2]

sounds like you have a leak

try this,close the air inlet and if there still air going in, find the source, plug it and that should help.

Jose

[matt]

About your pump, if you've cleaned the wet end and you know that the impeller is in good shape and is turning easily on the shaft, there's not alot more you can do. You have to be sure to remove all traces of scale from the impeller and shaft, using vinegar or diluted muriatic acid. You probably know this already, and if you've done it, your next step is to call little giant, they area U.S. company so there's a chance you could send them the pump and they'll rebuild it. IMO they're medium quality externals; way better than mag pumps but not as good as iwakis or pan worlds. See what little giant says; they may rebuild it cheap. If not, go for a pan world. The genX mak4 is only a little more powerful; it actually runs on less power, but has 3/4" out rather than 1/2". Both of these pumps running correctly would put out more flow under any sort of pressure than a mag 12, so don't worry about that being too much pump.

About your venturi, I'm not sure how yours is set up exactly, but the general idea is that water flow speeds up in the area of the air inlet, creating a pressure drop which draws air in. It's not uncommon for there to be some whistling or some sort of air noise. You can quiet that down with a foam cover. (like a foam windscreen on a microphone) If you cover up the hole, the water gets clear, right? then you take your finger off and it get bubbly again? If so, it's working, and I suspect what you feel is not air coming out of the venturi, but just some turbulence right around there.

What I can't figure out from your photo is: 1) What's the white fitting up high on the tube? I would have thought that's where the water in would go. 2) Where the output is, it looks like there are tons of bubbles; does this skimmer drain microbubbles into your sump? I bet there's an elbow inside the tube at the output so it draws from the very bottom of the tube, but it still looks very foamy to me. This is one of the reasons I build a box under the tube on my skimmers.

[RNall]

sounds like you have a leak
try this,close the air inlet and if there still air going in, find the source, plug it and that should help.

I have plugged the air inlet and it stopped the air flow. I only did this for a second and wasn't checking for leaks so I will do that tonight. Thanks again Jose!

About your pump, if you've cleaned the wet end and you know that the impeller is in good shape and is turning easily on the shaft, there's not alot more you can do. You have to be sure to remove all traces of scale from the impeller and shaft, using vinegar or diluted muriatic acid. You probably know this already

yep.

your next step is to call little giant

I will do that. thanks for the idea!

If so, it's working, and I suspect what you feel is not air coming out of the venturi, but just some turbulence right around there.

I will check again.

1) What's the white fitting up high on the tube?

Its a second port to be used for counter current action. These things come from PM with a tee off the bottom port and the top port tied into the bottom. I think it's supposed to provide 50 gph of counter current flow. I guess the previous owner thought it worked better without it.

2) Where the output is, it looks like there are tons of bubbles; does this skimmer drain microbubbles into your sump? I bet there's an elbow inside the tube at the output so it draws from the very bottom of the tube, but it still looks very foamy to me.

Correct, there is an elbow. This is an older picture, the LG isn't creating that much turbulence or bubbles right now. It does drop some bubbles into the sump but they go behind a baffle.

Thanks for all the help Matt!

[RNall]

Well, I plugged the air inlet last night and there was no more air entering the skimmer. So no leak. I was hoping there was one...

There is definitely air occasionaly coming out of the venturi. It's like it burps up air every few seconds. Could something be lodged in it? I wonder what would cause this.

[matt]

Can you post a close up photo of the venturi? I'm not sure what would cause what you're talking about, but remember that a venturi will work best with a particular range of water movement through it and especially with a steady flow. It's all about how much speed the water picks up in the venturi area, and consequently how much of a pressure drop is created. So your pump may have something to do with the burping. A typical scenario is that air enters the water at the venturi, creating foam, which means the water column expands in volume right downstream from the venturi, which causes friction, and with a weak pump, a slow down of the water, which can cause the foam to "back up" a little in the venturi area and interrupt the flow of air into the water stream. So, this causes less foam, which lowers the line friction, it speeds up, and the whole cycle starts over. Does this sound like someting that might be going on?