Got home from a late night at work today and all my fish were near the top, nitrites had a huge spike again. Did a huge water change (maybe 70%) and everyone looks back to normal. I'm hoping things stabilize soon, because my wife is starting to resent how much time I'm spending taking care of the tanks.
In happier news, I got my filled CO2 tank yesterday, and I built a prototype of my CO2 reactor. I haven't yet devised a good way to know if it's "really" working how I intend, but I did manage to get a jury-rigged bubble-counter going at ~5 bubbles per second through the reactor with little to no bubbles escaping the tubing....
The only flaw in my reactor design is that's PVC, so I really have no way of monitoring what's happening inside of it. I guess I just have to trust that everything is behaving as planned.
Also, it's a real PITA to stretch 3/16" tubing over a 1/4" barb, but I managed to get it over a couple of ridges with my heat gun and some needle-nose pliers. I could just build a proper coupler, but that feels like cheating :P