Skimmer input placement.

[OhMatic]

I am building another skimmer.
I have 4ft of 4in acrylic, and an air pump 2.13psi/1.41CFM.
Can anyone tell me how much of an air lift this pump will create in a 4in tube 4ft tall(with a 12in airstone)?

I'm planning on makeing several options for the skimmer so I can run it as a venturi or a CC airstone skimmer or both.(kinda an experimental skimmer)
I'm having a problem on deciding where to put the water input on the skimmer. I'm thinking I will put three inputs in the skimmer but I'm not sure of the exact placement.
also I don't know how much of an airlift the air pump will create and I was planning on using an adjustable height output to regulate the skimmer water level and the adjusters only adjust about three inches. any ideas other than just trial and error?

[Snailman]

Take the water in 4" - 6" inches down from the bottom of the neck. As far as air lift it will depend on how much water you pump down the chamber to fight with the air. Make a counter current skimmer and let the venturi go IMHO. You can adjust the water height in the chamber by adjusting the air or the input water. You need to consider the output also because it can siphon water out of the skimmer faster than you can pump it in if you don't set it up right.

[OhMatic]

snailman,
How did you come up with the 4-6inches?
Also I don't understand how an airlift would be effected by the amount of water which is pumped in the skimmer. Wont it lift the water to its max height as long as the water flow is not enough to push air bubbles out the output?
Also the output will have a syphon break.

[Snailman]

I came up with the 4" - 6" from a good guess for the skimmers that I have. I did not miss by far. here it goes, UltraLifeReef CC skimmer 3 1/2", Ron's Satltwater Heaven CC skimmer 7". If you need more information feel free to email me.

[DougL]

OhMatic;
My very humble guess is the air pump you have will not do it.
The old standby was the Tetra Luff,Which was 7.5 psi. The depth and difuser resistance cut output with a wood airstone on a 24" skimmer from 600 L/H to between 100 and 200 L/H.

For a 48" skimmer, I would look more for pressure.

Just random thoughts;

DougL

[OhMatic]

DougL,
Thanks for the reply...
The pump I have is a Medo its a linear piston air pump which are not like your normal diaphram air pump such as the tetra luft. (www.medousa.com)

Here are some specs for the Tetra Luft pump:
.09 cfm @ 1 psi
.05 cfm @ 3 psi
.00 cfm @ 7.5psi
This means that at 7.5psi the pump will shut down and pump no air. So when you say the Tetra Luft is rated 7.5 psi your saying that is the presure where it quits.

My pumps specs. (medo AC0602)
1.55 cfm @ 1 psi
1.41 cfm @ 2.13 psi
1.01 cfm @ 3 psi
So the two pumps are really not comparable at all.

Chris Paris did some actual tests on this pumps output and a tetra luft at differnt preasures. I can't find the spreadsheet now but its pretty impressive.

Anyway my concern is this air pump will be too much for a 4in diameter skimmer but I can divert some of the air pumps output.

my real question is how much of an air lift will this air pump make with a 12in air stone in a 4in diameter tube... Does any one know how to figure this out?

[DougL]

OhMatic;
Nice air pump. You are right, we were talking shut off pressure on the Luff.
When I saw your statistics, I assumed (incorrectly) that the 2.14 PSI was shutoff and the 2CFM was at 0 back pressure. :)
Oh well.

AS for your question, I don't know.
There should be an easy way to calculate the pressure it would take to pump down 48", but I don't even know that.

Good Luck;

DougL

[OhMatic]

DougL,
I'm sorry, what I wrote was not what I meant.
I should have said 1.41 cfm @ 2.13 psi