When you set up a heavily planted aquarium with everything that life loves — oxygen, carbon dioxide, nutrients, etc. — you should not be surprised that the very first thing that comes to call is algae. Here’s the algae in my new 40-gallon planted tank a mere two weeks after set up. I held off adding fish that would munch the algae because the specialty soil I selected is off-gassing ammonia that will kill fish and my filter system doesn’t yet have the beneficial bacteria established that will break down the ammonia. Patience is a virtue. Technical detail: yes, it is true, that lower PH with temps in the 75-77 degree Farhenheit range render the ammonia mostly harmless, but I don’t have a trustworthy thermometer yet and don’t want to needlessly risk fish.