Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
1) Keep the ammonia at 3 ppm once a day, OR bring it only as high as 1 ppm, but do that twice a day.
REASON: Some plants do not like ammonia, and 1 ppm is all they can handle. The bacteria need to be fed in a way that represents the constant low level of ammonia that fish will produce. 3 ppm once a day will get used up by the bacteria and they will have a few hours with no food, and that is OK. 1 ppm twice a day is just about the same, as far as the bacteria are concerned, but safer for some plants.
2) Keep the nitrite under 5 ppm. These bacteria do not do too well when the nitrite rises too high. If you need to do water changes for high nitrite, then you might add less ammonia for a few days, until the nitrite removing bacteria catch up.
3) Plants and bacteria use many of the same nutrients. They will do this when the tank is fully running, too. So the short answer is Yes, having thriving plants will mean the bacteria population is smaller.
The more extended answer is that plants are also part of the bio filter. It does not matter whether the nitrogen is removed by bacteria or plants, as long as it is removed.
Having the plants well established and thriving when the fish are added is a very good way to make sure the plants are indeed doing well, and will handle the ammonia, CO2 and other things from fish, fish food and whatever else you add.
Substrate: Nitrifying bacteria live on all the surfaces in the tank. This includes the substrate. They do not live on the very top of each grain, these bacteria do not like the light. They will live on the under side of each grain. They will not thrive in the deeper parts of the substrate. They need high water flow because it brings them the oxygen and ammonia they need. This was the secret to under gravel filters: By improving the water flow through the substrate the bacteria could colonize more of the substrate, so a UGF was a pretty impressive bio-filter.