I had issues with bell style diffusers, do you get a good dissolve rate or does it burp off gasses often?
I think I would want my input closer to the bottom so fine bubbles are forced to flow through more moving water.
No CO2 doesn't burp through at all. Trick is to make hole for water small enough to prevent it and big enough to go through without overflowing from top.
Yes I agree about moving input port to the bottom.
I am doing new version right now.
Another change would be to make long side of the box much narrower.
It doesn't make any sense to have it thick as it is now, it just takes space