Aquarium and Fish Maintenance Part 2: Aquarium Water Chemistry

Posted By: Matt Allen

What does it really take to keep your aquarium clean, and your fish happy?   Last week we discussed the importance of watching and observing the fish in your aquarium.  This week we will talk about the water in your aquarium.

You need to ask yourself the question, How clean is my water?  Clean water will keep your fish happier and your aquarium thriving.  Aquarium water chemistry can be very complex and for this post, we will keep things very simple.   The water in your aquarium is affected by the fish, the food that you feed your fish, the plants and algae that are in it, and the filter that helps keep it clean.  You feed your fish, and your fish produce waste. Over time this waste builds in your aquarium.  The waste is measured by testing your water for Nitrates.  The only way to reduce the waste/nitrates is to remove water and replace it with clean, new water.  This is what we call a water change, and a general rule of thumb is to remove 25% of your aquarium water once a month and replace it with clean dechlorinated water.  Live plants and algae also reduce nitrates in your aquarium.   Nitrates are a natural fertilizer for aquarium plants and algae.

rainbow fish

Removing too much water, or cleaning too much, can also have a negative effect on your aquarium.  When you remove water you take nitrates out of the water but also take out nitrifying bacteria that help keep your aquarium clean.  Over cleaning can remove too much of these bacteria. These bacteria are throughout your aquarium on the surfaces of the glass, gravel and in your aquarium filter.  Most aquarium filters are designed to help colonize these bacteria within the filter.  The bacteria are then exposed to the aquarium water that passes though it and in turn remove other waste called ammonia and nitrate.  These two chemicals are also a result of fish waste and are controlled by the for mentioned bacteria.  The process of fish waste being broken down in the aquarium is called the “Nitrogen Cycle”.  If you wish to read more about the nitrogen cycle there are a few links posted at the bottom of this article.  Here are some simple rules that can help keep your aquariums clean through the years.

  1.  Never overfeed your fish.  Small meals two to three times a day work best.  Excess food on the bottom of your aquarium will lead to bad water quality.
  2. 25% water changes once a month.  Small water changes one a month help keep your fish happy and your water clean.
  3. Change you filter media once a month – Try not to change the media on the same day you change your water.  If you change your water on the 1st of the month try to change your filter on the 15th
  4. Test your water if your experiencing any issues or when you visit your local fish stores.  Have your store check for Ammonia, Nitrite, Nitrate and Ph.

Next week we will talk about the importance of keeping the equipment in you aquarium working properly.