Aeropars said:
In practical terms relating to the CO2 reactor, you take a length of airline tubing and insert one end in the reactor and the other end of the tubing you place anywhere in the water flow just before the input to the reactor. This creates the venturi loop which removes any pocket of gas in the reactor.
My understanding of the science is not good enough for me to be able to decontruct it concisely for you. A bona fide explanation of the science can be found here, but you might find it a bit esoteric....
http://en.wikipedia.org/wiki/Venturi_effect" onclick="window.open(this.href);return false;"
To expand in the comment in my last post about whether this would be of any use to you; if you were to notice a large pocket of gas at the top of the reactor and one end of the venturi loop was terminating inside this gas bubble it would effectively remove the gas bubble. The gas has to physically enter the venturi loop to be removed though, so if you can not actually see any build up of gas in your reactor then the venturi loop won't help you.
It sounds like you have a gas build up somewhere though, or you wouldn't get the spurts out of the filter outlet. To my mind the logical place is the reactor, but you might have other factors that are having more of an influence that I haven't thought of.
If you want to get your head around the venturi concept further I recommend you to do what I did which is to spend a few hours poring over the links to the venturi I posted before. There is a picture of the internal reactor that clearly shows the extra tubing for the loop and the placement of it.