As often happens, I went through a period of neglecting my tanks, especially my (55-gallon) main tank. It's the kind of thing that happens to almost every aquarist at some point in time. The main tank has always been light-deficient - while most people recommend 2-3 watts per gallon* for a planted tank, my plants were forced to get by with approximately 0.55 watts per gallon. As long as I was feeding them Flourish Excel, the plants seemed happy (especially the Cambomba), but once I quit, only the Java fern and Echinodorus ("Amazon swords") did much.
While the main tank was suffering a lack of plant growth (somewhat masked by the expanding Java ferns), my other tanks were experiencing the opposite problem - too much plant growth. The plant tank was covered by an emergent carpet of Ludwigia and Bacopa monnieri; the tank itself had turned into a mass of roots. The Otocinclus tank was similarly overgrown, although instead of being covered by emergents, it was covered by a think layer of floating plants.
At the end of July I shook myself out of my torpor and started moving plants from the plant tank to the main tank. I realised that I had to upgrade my lighting, but at that point in time, it just wasn't an option. I replanted a lot of Ludwigia and a little Bacopa into the main tank, and cleaned up the mass of floating vegetation (I either replanted the stuff, or got rid of it). And then I had to leave it all alone for a week and a half.
One of the main reasons I wanted to clean out the plant tank was the fact that we would be gone for a while. I don't have a timer on that tank, so I have just left the lights on when we are gone. One time I returned to find the tank a thick mass of hair algae - so thick, in fact, that the water was obviously not circulating (some areas were very warm, others were far too cold). While that is likely to be less of a problem in summer, I still wanted to clear out enough vegetation to give it some room to grow. But moving plants to the main tank created a problem - did I really want to go to all that effort, and then watch the plants turn into spindly things before slowly dying? While a lighting upgrade was in order, I had neither the time nor the money for anything of the sort.
On the way home from Michigan I finally stopped into Preuss Pets in Lansing, Michigan. A friend of mine has been saying great things about them for years, all the more now that they have moved to a larger place (more later). I ended up buying a really nice new lighting system, and I now have two 54 watt bulbs on the tank. Not too surprisingly, the change was remarkable. I have also continued to move plants from the plant tank to the main tank. It's too early to say home much of it will really take (a lot of what I transplanted was emergent in the old tank, so it will have to adapt to being submerged), but the tank looks great and the fish seem happy, poking around in the new vegetation.
* It's actually more complicated than simply "watts per gallon" - not only does the light output matter (not all 30-watt fluorescent bulbs are the same), it also matters what wavelengths the bulbs produce.