They key (IMO) is as much live food stuffs as possible, lots of plants, and tannins, tannins, tannins! The
Philodendren scandens put lots of roots into the water, as do the Lemna minor and Phyllanthus fluitans, sucking up nitrates and catching particulate matter that otherwise would float about due to the lack of a mechanical filter. The most maintenance comes from removing the profuse growth of the floating stuff and winding or trimming the philos back down. I also occasionally pull off leaves from the swords if I feel they are getting too large. Scraping algae off the glass is a weekly to semi-weekly task (about 45 seconds with a blade), as it is a very high light tank. The amount of algae buildup is minimal, but is more when I've removed some of the floating plants which provide decent shading (I've not noticed that any hair or thread algae present...knock on wood). Any stuff I've removed gets used as top dressing/fertilizer for various house plants (I try not to waste anything!) I personally don't use CO2 injection, because I'm cheap like that, and figure any faster growth rate would just be a pain to deal with. The tank has been up and running for just over a year. The only major concern was an initial outbreak of green water...pea thick. That was handled easily by adding daphnia (pulex and moina) which cleared it up nicely before becoming fish food. Once the higher plants were established (about a month), things have been stable ever since. It is like Zen, I guess. Patience, patience until the system is stable. There is no better cure for green water than introducing filter feeders! Take a floating breeding trap and place it in your tank, fill it with daphnids and just watch! Moina seem to be the best for most tropical tanks, as they seem to fare the higher temperatures better.