How I can get the nitrates in my aquarium?

The nitrate level was over 200, so I emptied half the water in my tank of 300 liters. Then clean the bottom with a suction hose, and turned the raw cotton. Nitrate levels are around 100 …. remains very high. Do I have to pull everything, including the filter? By the way the filter is a biological being, with several layers of different things. Currently there are no fish in the tank. The last fish died a few days. The ammonia level is 0.

If you intend to get more fish? If so, to shed its wool filter was a mistake. That is where most of bacteria that are responsible for the waste cycle in the tank of residence. Unless that was falling apart, just clean in a separate container with some of the old water tank. If you still have it, and not dry or contact with anything to be harmful to fish, I could still do this and * * rescue. To lower nitrate levels, just follow the changes of water. Use a gravel vacuum to deflect any debris that has gotten stuck in the gravel. As it decomposes, it forms ammonia that eventually changed into nitrate by bacteria. Without fish, you can change almost 100% water, but I DO NOT want to do is let the gravel or the filter to dry. That will kill the bacteria remain. Even if you can not recover their old media, the gravel still have some bacteria in it. When refill tank, add water conditioner to remove chlorine / chloramine, because these bacteria are killed too. So unless the fish died for a reason related to water quality, your tank should still keep the bacteria needed for waste cycling and be sure to add a few new fish. If you are going to take weeks able to obtain new fish, you might want to add some pure ammonia or fish food to decompose to release ammonia to simulate the presence of fish in the tank to keep the bacteria alive.

Aquarium Algae Control by Bleaching, Cleaning Remove green hair & brown algae, diatom bleach