Why use venturi over air pump?

[silverwolf72]

Looking threw several threads seeing people go thew all the work of modifying there venturis to get more CFM I was wounder why not just use an air pump so that you have direct control over the CFM?

 

[serpentman]

I believe this is because most conventional diaphragm airpumps don't have the output necessary to run a skimmer. You would need a heavy-duty air pump which would cost more money, run more electricity and sound like a diesel truck.

 

[luke33]

I've tried this on one skimmer and it was to much.....i'll be trying this again this weekend with a stronger NW pump....it will be in the woot odyssea skimmer thread.

 

[wife no likey]

I'm using a coralife sl-38 on my 1262 meshwheel. I currently have it pushing about 40scfh into the pump.

Not only am I injecting more air than the single pump would be able to pull, but the wattage draw also significantly decreased.

The pump was pulling about 100w when using a venturi. It now draws 70w, and the air pump only draws 20w. I am using less wattage combined, and part of that is not exposed to water = less heat.

 

[silverwolf72]

how many CFM is 40SCFH? Is SCFH = square cubic feet per hour?