What is the easiest (and cheapest?) way to lower nitrates in a freshwater aquarium?
The cheapest way is to due one of these aggressive water changes where you drain out 80% of the water You can see several ways to lower Nitrates and explanations on what is happening here. http://freshaquarium.about.com/od/watercare/a/nitrates.htm But the cheapest of these methods will be this one http://saltaquarium.about.com/cs/nitratecontrol/l/aa091901.htm which is merely a form of aggressive water change. The problem with doing standard water changes of say 25% every week is that it will take a long long time to get nitrates down if they are very high, which they are in the majority of peoples tanks. Live plants can also help as they use nitrate but you asked for the cheapest. The water changes are pretty easy also since they require no real thinking. I use a large plastic tub or even trashcan to put water in overnight, filtered water is also a good option. Using a carbon and zeolite mixture in your filter instead of just carbon will also help since your tank will have slightly les
Nitrates are the end product of the bacteria cycle that converts the ammonia in your tank into less harmful nitrate. Technically it goes from ammonia to nitrite, and then from nitrite to nitrate. Nitrate is used by the plants and algae in your tank as food, however your tank is probably producing it much more quickly than your plants are using it. Your best bet is to simply do weekly 25% water changes to lower your nitrates. If your nitrates are really concerning you, do water changes every other day until the level drops to a safe point.
