Got some more anubias. It's hardy but that first one I put in had started to melt a little bit. Got some API anti-algae at the LFS, carbon's out of the tank, so we'll see how it goes. New light cycle doesn't seem to be having too much of an effect but it's good practice, so it's staying. I brought a sample of both tanks to test for phosphates, since only one was having an issue. Sure enough, the problem tank's test goes blue; about 1.0ppm. OK... try the other one. Nothing. For a while. Then slowly, same shade of blue, then darker and darker. Over 3.0ppm. LFS guy explained that it was lower in the problem tank because the algae is using it and growing, whereas the good tank has the giant water sprite established and it's out-competing the algae. So, I bought a test and tested my tap water. See below; she's bad. I guess we'll see how this API product goes. LFS guy doesn't like Seachem for some reason, but they and others make filter media that absorbs phosphates too but he said not to use it yet because if it's combined with the API and it drains all the phosphates, it's bad for the plants.
The good news is that none of this bothers the fish at all; they're doing good. The bad news is, if I don't fix this, my plants are going to keep dying. I'm rooting for API on this one right now.