If I am going to use an inline CO2 reactor with a Fluval 304(260 gph) what will the GPH be when it gets to the tank? I assume this fixture will rob quite a bit from the filter, by adding back pressure.
I dont think there is a way to calculate that out easily. I would not worry about it unless you are right on the edge of the flow you want. Plants dont typically need all that much flow, just a good consistant motion thoughout the whole tank.
I am not really worried, I am just curious. Mainly I was hoping that people who used them would be able to guestimate the loss in flow like it cuts flow by 50%....25% something like that. I know there would be no way to really tell aside from hooking up a flowmeter.
If it's built to match the size of your tubes and has no section smaller than the inner diameter of the existing tubing I'd think it would not effect things much at all. After all it expands the inner diameter to slow down the current speed and then brings it back to normal size, there should be little to no back pressure. If the flow is too fast and you need to slow it down using bio balls then what you really need is a bigger reaction chamber rather than obstructing the flowrate even further.
I'll try the gallon jug idea. I am planing the reactor chamber to accomodate a much larger tank for the future when I upgrade, and I am planning on using bio-balls as it stands right now. I do the tests and let you guys know what I find out. Thanks for the tips.