Is the outlet at the top or bottom? I believe you want the water to flow down, against the rising CO2 bubbles. Maybe I'm misunderstanding, when it's vertical, large bubbles come out? Are the pushed down and out? That sort of does sound like too much flow.
Yea the flow is from top to bottom. When its vertical larger
bubbles come out, but theyre still fairly small. I just noticed that theyre a lot smaller when i tilt the reactor at an angle.
Im not really trying to troubleshoot a problem or anything though. It works really well so im not going to change anything. Just wondering if anybody else had noticed that it diffuses better at an angle. I did a little searching on here earlier today and found that a lot of people people had noticed the same thing. 5 or 10 people mentioned it in Rex's thread on how to build one.
With a 2" diameter reactor on an XP3 you might get bubbles pushed out on the bottom. I went to a 2.5" diameter and that worked. It's not so much the length, but the diameter that slows down flow and gives the bubbles a chance to dissolve.
Regarding accumulation of gas, have you noticed this happening more in the afternoons? Or do you have the same issue in the mornings? If there is a lot of photosynthetic activity in the tank, you might get an accumulation of O2 (not CO2) in your reactor. O2 doesn't dissolve as readily as CO2 so it tends to accumulate and create some noise. There are a few things you can do to combat/minimize this... if that is what's happening.
People have used smaller reactors on eheims with more flow than my XP3. Besides, length has more to do with how its diffused then width. Technically, if you had a long enough hose(it would need to be like 8' long lol) you could do this with the 5/8"-3/4" hose thats on your filter without needing a reactor as long as the initial bubble size was within a certain percentage of the overall diameter of the tubing. Its been 10 years since my fluid dynamics courses, but im sure i could dig up the calculations to support this, though id rather not have to dig out all of my old textbooks
The noise starts around 20 minutes after the co2 comes on, which is about how long it would take for the co2 to pool at the top. The noise doesnt change at all until maybe 15-20 minutes after the co2 cuts off(takes that long to diffuse the remaining co2 in the reactor). I dont think its o2 thats getting in the reactor. I cant imagine how it would get in there because there shouldnt be enough pressure and turbulence to cause cavitation. Before i installed the reactor i never had bubbles from that filter so i cant see why it would start now.