Thank you ka NUK and Wicket_lfe (which I read first as "wicket elf"--interesting visual)
I think there is some trapped air as a result of bubbles from the HOB filter, but there is clearly pearling from the bamboo and the HC that isn't trapped bubbles--it's coming from the newest leaves and is on the top, not underneath. Not a whole ton, but I have taken it to mean that I'm doing something a little bit right, at least. I can hope!
I thought I also understood that in nature surface agitation is one of the things that provides CO2, and the bubbles do seem to sort of get trapped in the turbulence and take a long time to resurface. That has been my best guess. But maybe I'm confused?
I read differing opinions on CO2 in this small of a tank--4g. I do dose Excel, 1 mL daily, but my schedule is too erratic to do it at the same time every day, so sometimes I go without once the lighting period has ended. I was mistakenly overdosing there for a while, and it did seem to help the algae problem, but with the shrimp I understand I should be careful.
At 8 hours, I thought that would be short enough of a lighting period, but maybe shorter?
The stellata bulbs--I might be a bit misleading. I started with the dry bulbs and it was happy and sending leaves to the surface for a few months, and then sort of...fizzled in terms of growth. So I got wet (sprouted) ones from an ebay source a few months ago, and they were partially rotten. I cut off the rotten bits and just shoved the remainder in there. So far so good, and I do think they are taking hold. Have also added small bits of root tabs under them, to see if that helps.
I'll keep posting. Thanks for the encouragement!