OK, got home from work to a possible disaster. The pH had sank thru the floor. I believe it to be a combination of more CO2 and no aragonite (crushed coral). I did lots of small water changes to correct and now we are back up to 6.6pH. The ammonia looked good (I'm guessing less than 25ppm, but the test kit is not bullseye accurate), so I took out the bio media from 1 fluval and replaced it with the aragonite. I also took out all the remaining driftwood and put it in a low-lite 150. I figure the effect it will have on 150 gallons of water will be lesser than in the 55. I also turned off the CO2 for tonight. I may restart it tomorrow. The bichirs looked just fine, but the jewels are having a rough go of it, as are the bristlenose. If I am erring grossly, let me know.
P.S. I plan on getting some hornwort to add. The stickies suggest it will do well, grow fast and use up nutrients.
P.P.S. Oddly, the beard algae is not doing so well now, it is much easier to remove from the leaves. The slime algae is still cooking right along, though. It grows fast.