DIY skimmer tuning issues and proposed solution

[tigé21v]

I love DIY. I think this should be able to work.
If it were me, I would

-run hard plumbing from the pump to the skimmer. And a larger diameter of pipe also.
If you were to leave the infeed in the same spot on the skimmer, be sure there's a 90 forcing the water down (I cannot tell from the pic if there is currently one or not.) I don't think it would hurt if you added a couple of inches to the 90 (inside the skimmer body) to get the air/water mixture down a little further into the skimmer. Jsker's suggestion would be my preferred way to feed the skimmer. But it seems like you may not have enough room to do so. Especially if you were to add a venturi.
-add a venturi. Bobman offered up some sound advice. For a few bucks, you will be much, much happier with both the skimmer's tuning and performance than you will be trying to get your pump to do something it was not designed to do. And I'll admit I'm not 100% certain, but if indeed your pump is cavitating in the true sense of the definition, I think it'll eventually tear up your pump. Put the venturi on the outfeed of the Mag. Be sure to use the needle valve to control the flow of air into the skimmer, as the air may be overpowering for that particular neck. (I think you may end up resizing that neck before everything is said and done.)
Venturi air inlets are prone to clogging, just like the air inlets on needlewheels, it just seems to happen faster. It should be easy enough to set up some sort of way to flush it with your Apex. Either a small pump or a solenoid. You could just shut the skimmer off for a little while every few days. Or set the venturi up so that it is pulling the air from the skimmer collection cup like the LifeReef skimmers. The moist air from the skimmer cup helps to keep the air inlet from clogging.
You'll get the kinks all worked out. Be sure to post pics of it doing its thing once you are happy with it!
And yes, at least in my experience, water changes affect skimmer performance. Mine always seems to go a little crazy for a while after a WC.

 

[jgvergo]

I love DIY. I think this should be able to work.
If it were me, I would

-run hard plumbing from the pump to the skimmer. And a larger diameter of pipe also.
If you were to leave the infeed in the same spot on the skimmer, be sure there's a 90 forcing the water down (I cannot tell from the pic if there is currently one or not.) I don't think it would hurt if you added a couple of inches to the 90 (inside the skimmer body) to get the air/water mixture down a little further into the skimmer. Jsker's suggestion would be my preferred way to feed the skimmer. But it seems like you may not have enough room to do so. Especially if you were to add a venturi.
-add a venturi. Bobman offered up some sound advice. For a few bucks, you will be much, much happier with both the skimmer's tuning and performance than you will be trying to get your pump to do something it was not designed to do. And I'll admit I'm not 100% certain, but if indeed your pump is cavitating in the true sense of the definition, I think it'll eventually tear up your pump. Put the venturi on the outfeed of the Mag. Be sure to use the needle valve to control the flow of air into the skimmer, as the air may be overpowering for that particular neck. (I think you may end up resizing that neck before everything is said and done.)
Venturi air inlets are prone to clogging, just like the air inlets on needlewheels, it just seems to happen faster. It should be easy enough to set up some sort of way to flush it with your Apex. Either a small pump or a solenoid. You could just shut the skimmer off for a little while every few days. Or set the venturi up so that it is pulling the air from the skimmer collection cup like the LifeReef skimmers. The moist air from the skimmer cup helps to keep the air inlet from clogging.
You'll get the kinks all worked out. Be sure to post pics of it doing its thing once you are happy with it!
And yes, at least in my experience, water changes affect skimmer performance. Mine always seems to go a little crazy for a while after a WC.

I have a 90 degree elbow and some PVC in the skimmer that directs the incoming water to the bottom of the skimmer. My contact time is pretty good I think.
I am *very* constrained on space in the sump. What I have fits pretty perfectly b/c I designed everything to fit together and built everything myself.

You said "put the Venturi on the outfeed of the Mag". Two questions (which clearly demonstrate how much of a newb I amd:)) 1) When you say "venturi", I assume you are talking about a full pump like the kind Ed linked to earlier in this thread? and 2) What is a "Mag"?

As for skimmer behavior, I get much LESS foaming after a water change!

 

[tigé21v]

No worries, every single one of us were newbs at some point.
Google mazzei venturis. it's a fitting that is attached to the out feed side of your pump. It works on a pressure differential to pull in air to the water going into your skimmer. If you keep the skimmer plumbed as you currently have it, it should fit right between your pump and the skimmer.
As far as Mag, I thought I read you were using a Mag7 as the feed pump? if not, sorry for the confusion.

 

[jgvergo]

No worries, every single one of us were newbs at some point.
Google mazzei venturis. it's a fitting that is attached to the out feed side of your pump. It works on a pressure differential to pull in air to the water going into your skimmer. If you keep the skimmer plumbed as you currently have it, it should fit right between your pump and the skimmer.
As far as Mag, I thought I read you were using a Mag7 as the feed pump? if not, sorry for the confusion.

Ahhh, this is really helpful. I think if I find the right mazzei venturis (or something like it) that will do the trick! It provides the function I need and it will fit too!

 

[tigé21v]

Mazzei makes about a hundred or so different sizes. Their website lists them all, and can be a little daunting..
I have a skimmer made by MTC that runs two 684's. I tried to replace them with 784's, and the performance wasn't as good . A 684 would probably be a good fit for your skimmer. Or maybe one a little smaller.
What size pump are you running?

 

[jgvergo]

I am running an EcoPlus 728315 Eco 633 Submersible Pump, 594GPH.

 

[jgvergo]

Does anyone have experience with the
A2Z Ozone Venturi Injector
venturi?

 

[tigé21v]

A friend of mine purchased a couple of these off ebay. They worked fine for him. They don't seem to perform as well as the Mazzeis, but then again, they are about half the price. Also, and an important point- he is running a much, much larger pressure-rated pump on his skimmer (Iwaki MD100).
A 1" is much too large for your pump. The water being forced through the restriction of the fitting is what causes the air to be drawn in through the small hole on the side. The more force (pressure) the water goes through the fitting, the more air it will pull in. I'd probably go with a 1/2" or 3/4", probably the 1/2". I think your pump may be a little on the small side to get the best performance out of a venturi, but the 1/2" may work.

 

[jgvergo]

So I got a 1/2 inch A2Z Ozone Venturi injector and I think my pump is indeed slightly under powered. Does anyone know what is the typical GPH for a skimmer pump that services a 115 gallon system? I guess I'd need to know the max head too?

 

[bobman]

I got a mag 9.5 on my skimmer but I use the lifereef venturi. Should be pretty much the same though