OK, so the test results are in. Ammonia levels in between 0 and 0.25 ppm (I'd guess about 0.15-0.20 by color), nitrite levels in between 0.25 and 0.50 ppm (I'd guess about 0.40), and nitrate levels at right about 30-40ppm. Not the best results I know, but considering the circumstances they could be worse. I went ahead and added more Stability as per instructions. The heat looks to be maintaining 78.5F, which while pretty much ideal still frustrates me because the house isn't that chilly and the heater is turned up full blast. That heater is going back to the store tomorrow for an exchange or refund; maybe the next one will do the job appropriately.
Fishes are still happy and eating well (just once today, instead of 2-3 times as previously). I checked the timing on my lights (they were way off), so I should now have a pretty good 10hr light cycle from 8am-6pm.