Sponge filter - Flow rate issues

[Hari]

Hi all ..I made a simple sponge filter as shown in this video https://www.youtube.com/watch?v=eIXyFZohRCA

I am using a Tetra Whisper  air pump (40 gallon). I find that the water flow rate is very low (just flowing drop by drop) when I hold the pvc pipe outlet just above the water surface of my 40 gallon tank. Is there anyway to increase the flow rate? Should I make the holes smaller? Or is this flow rate sufficient?

[Regalblue]

As long as air is coming up the tube, then there will be vacuum.  Whether it's sufficient or not is hard to tell without actually seeing the filter.

[Ron]

My connection isn't great, so I'm not going to watch the 10 minute video. How about a picture of what you built as suggested?

I did my own DIY filter that is similar in concept: http://michigancichlid.com/simplemachinesforum/index.php?topic=7472.0

The flow rate is going to depend on a few things. First is the diameter of the uplift. Too small and you're flow rate is limited. Too large and the water can move to the side while allowing the bubbles to travel past.

Second is the length of the standpipe and the length the bubbles travel in the uplift tube - the longer, the better (similar to increasing velocity in a gun barrel if you're familiar). Of course there is a limit to how long you can go depending on the height of the sponge, the tank, and the pressure the air pump can provide.

The size of the bubbles may also influence the flow rate - I've had better success with larger bubbles for more flow rather than bubbles diffused by an airstone or such.

The intake end of the uplift tube can also impact the maximum flow rate. Too small and even with a lot of vacuum it will choke off the flow rate.