Same here, everything pH, ALK related is rock solid. My bubble screen been going for 8/9 weeks and growing nice thick green, so much so that I have put a split in my screen trying to get it off during cleaning. Maybe I can glue a few patches of new screen on it to stop the split from spreading all the way across the screen.
Wopadobop - when you started putting bubbles on the waterfall, did you see any burning or change in growth, mine did almost immediately and took a few weeks of lower lighting to get acclimatised again. Now my lighting has gone back to guidelines the growth is great. I have a feeling that the bubbles are improving light distribution on the screen through bubble refraction, shooting light off in all different directions to the algae on the screen, as well as co2 delivery.
Apparently, co2 hydration into carbonic acid takes 23 seconds. Therefore any contact by co2 at the waters surface less than 23 seconds should not be able to deliver co2 to the water column. I think that's where the micro bubbles created by the waterfall bubble screen have an advantage over the UAS ( especially if combined with a sump where micro bubbles are not a problem ).
Micro bubbles can stay in the water for long periods, especially if constantly recirculated over the screen therefore exchanging depleted co2.