Riser Tube Height? Help needed...

[nreefer]

I got my hands on 30 inches of 15 inch diameter tubing. I made a funnel that tapers to 6 inches for my 6 inch OD riser tube. Question is how tall should me riser tube be? The collection cup is 8 inches tall and I figure I want the riser tube to stop 2 inches from the lid of the collection cup. I need a little space from when the 6 inch riser tube starts to when it enters the collection cup for the removal of the nylon screws that compress the two flanges that attach the riser tube to the funnel.

The skimmer is fed from a Needlewheel OR 3700 and 2 x 3/4 inch mazzi 784 injectors. I have tried the skimmer with a 3" OD riser tube that is 10 inches long and it was way too constricted and the bubbles were combining too quickly forming large unstable bubbles.
Any hint/thoughts would be greatly appreciated.

Thanks

 

[shelburn61]

I'd check out pictures/schematics of bubblekings or similar large skimmers to get an idea of proportions.

I would also suggest feeding with the 3700 or one of the mazzei's and running the rest recirculating. JMO

 

[nreefer]

Thanks. It is already being fed by the two Mazzei venturi's and the OR 3700. The total volume of the skimmer is 26 gallons, and each mazzei is being fed off a large pump which also acts as my return pump. (Sequence Hammerhead split into a T).
From my calculations each venturi is feeding the skimmer with about 400 gallons of water (basing the PSI of the Hammerhead at the venturi's to be around 10-15 psi.) and the way I have my OR pump running it is above the skimmer in a frag tray that gets fed from the overflow of the main tank, so there is no head pressure, in fact if I turn the pump off it still feeds the skimmer through a 1" spa flex tube. I built a venturi for the OR needlewheel so when it is on full it injects more air than possible with a traditional recirculating setup. (I figure this because the flow after the OR pump greatly reduces, probably down to 300-400 gal/hour with the air valve open and it looks like it would cavitate the pump if there was any heat pressure.)

So with the construction I have now i can only really change to the OR pump from being a feed pump injecting air to a recirc. pump injecting probably less air and then feeding via gravity into the skimmer.
With this setup I could control the amount of water flow through into the skimmer. Right now I have probably around 1200 gph flow which may be too high and causing alot of turbulence. Another way to reduce the turbulance would be to do as I suggested in my first post and have my reducing cone go from the current 15 inch pipe to a 6 inch OD riser instead of the current 3 OD inch riser it have. More like the BK or Deltec skimmers.
Does that make any sense?

 

[nreefer]

While I'm on the topic, does anyone know where to find the threaded fitting that fits the intake on the OR pumps? I think they are Metric threaded...or is there a mod out there somewhere?

 

[Saltybob]

Just by chance I was just looking at it
http://www.reefcentral.com/forums/showthread.php?s=&threadid=626795