Cleaning your aquarium is something of a balancing act. You need to remove the “bad” dirt while still keeping plenty of the helpful bacteria that have built up in the tank. You also need to be sure to keep your fish safe and calm during the cleaning process.
It is helpful to follow a specific order when cleaning your aquarium, to avoid stirring up more debris into an area of the system you have already cleaned. There can be a bit of a chain reaction as you disturb different parts of the tank and this cleaning sequence can help minimize the adverse effects.
Start cleaning your aquarium by scraping the algae from the inside walls of the tank. This can be done using a variety of products, such as a magnetic algae scrubber or long-handled scrubber pad. Be sure to use scrubbing pads specifically for use in an aquarium; pads for regular household use may contain chemicals that are harmful to your tank.
After the glass is gleaming (at least on the inside), remove any decorations, large rocks, or artificial plants. These should be scrubbed with your algae pad. Do not use soap on anything you plan to return to the tank. Even a small amount of detergent remaining on a decoration can cause problems for your fish.
The next step in cleaning your aquarium is to clean the gravel using a water siphon. You will need a good-sized bucket that will hold the dirty water coming out of the fish tank. Don’t use too large a bucket or let it get so full that you cannot move it to dump it out.
Use an aquarium safe cleanser on the light, hood, and outside glass of the tank. Regular household cleaners can be extremely toxic to your fish; be sure the product you use is labeled as aquarium safe.
The final step in cleaning your aquarium shouldn’t occur right away. After everything else is cleaned, you will need to clean the filter. It is important to wait a few weeks before cleaning the filter. By cleaning the fish tank, you disturbed all of the bacteria in 
the tank, both good and bad. If you clean your filter immediately after cleaning your aquarium, you will remove much of the healthy bacteria that has built up in the tank. This could cause a dangerous spike in the ammonia level or huge swings in the pH levels. Either can be toxic to your fish.
Once your tank has had a chance to rest for a few weeks following the initial cleaning, you can safely clean the filter. This final step in cleaning your aquarium will leave your system not only clean, but also healthy.
