A Beginners Guide On How To Clean An Aquarium Properly

Cleaning an aquarium is not hard, but it does require work and the right set of tools. Anyone with a fish should clean their tank regularly. It can seem like a hassle, but this is a necessary step for your pet’s health and longevity. 

Aquarium cleaning can involve several tasks. You need to get rid of algae, floating debris, and organic material. You also need to wash certain items in your tank such as your filter and decorations. 

There is also regular maintenance like doing biweekly 25% water changes to reduce nitrates that are dissolved in your aquarium water.

I will show you how to clean your tank in this article step by step, but I can’t tell you what your specific tank might need in terms of cleaning. Cleaning requirements can depend on a multitude of factors. The temperature of your tank, the type of tank you have, the filter you have, and the lighting in your tank all play a role. Consider these things, and do a little bit of research to make sure you are cleaning your tank enough. 

Step 1: Prepare your aquarium for cleaning

Before you do anything, wash and dry your hands first. You don’t want to infect your aquarium with bacteria and other germs. Next, you can prepare your tank for the cleaning. Don’t just take out water from your aquarium, make sure to turn off the devices in your tank first. 

Beautiful planted tropical freshwater aquarium with fishes. Aquascape.

This includes filters, pumps, and heaters. Turn them all off. If you are doing a thorough cleaning you should also remove decorations. Artificial plants and decorative rocks fall into this category. I will instruct you on how to wash these items later on so set them aside.

If you are planning to remove your fish, do this now as well. However, I would refrain from removing your fish as this often is more stressful than leaving them in. We are not going to remove 100% of the water anyways.

Step 2: Get the tools you need

Next, you will need to gather up the necessary items for your cleaning. This is a list that I would recommend:

  • You’ll need a siphon gravel vacuum
  • An algae scraper or pad
  • Get a bucket to put the old water in
  • A new cartridge for your filter if you are changing it
  • At least one towel, but probably more
  • New prepared water for your tank
  • A kit to test your water
  • A thermometer to measure water temperature
  • Water heater if you need to modify water temp
  • Powerhead and salt mix if you have a saltwater tank

When you are preparing to change your water, make sure to treat your aquarium water to remove chlorine and chloramine. I have written an article about treating your water in the past, which you can check out here. In addition, if you have a saltwater tank, you’ll want to have a salt mix prepared and ready to mix into the water later.

Step 3: Remove some of the aquarium water

How much water you take out will depend on the schedule you choose to follow. We outlined how much water to take out at the beginning of the article. Whether you plan to take only a quarter of the water out or ten percent, you will need something to get it out. Use your siphon gravel vacuum to suck water out and clean up your gravel. Get your bucket ready to collect the old water from your tank.

Make sure the siphon isn’t picking up too much gravel though. Use your thumb to cover the other end of the tube. This will slow the vacuum down and give the gravel time to settle back into the tank. Some siphons have a valve to control suction though. 

Water will move up through the tube as should the waste on your gravel. Keep the vacuum on and move it around your tank. Don’t turn it off till you have cleaned all your gravel, and have gotten the amount of water you want out of your tank and into a bucket. Keep this water it will be used later.

Again, most tanks won’t need to be fully drained of their water. If you clean your tank on a regular basis you only need to take out a portion of your water! This is really important, because changing 100% of the aquarium water will give a shock to your fish as the parameters change too quick.

Step 4: Get rid of algae

After this step, you will want to start getting rid of the algae in your tank. Overgrown algae is never ideal for an aquarium. Use a scraper to get the algae off the glass surface of your tank. If you want, you can use a magnetic algae scraper to make the process easier. 

This type of cleaner has two magnets and is covered with soft felt material. You put one magnet inside your tank. The other one goes outside your tank. This way, you can drag the outer magnet around the aquarium. The inner magnet will follow and remove algae inside your tank with little resistance. 

hand cleaning aquarium using magnetic cleaner.

This is a lot easier than scrapping your tank from the inside. But again, this is up to you. If you have an acrylic tank also be mindful of the materials your scrapper uses. Acrylic scratches more easily than glass, so you don’t want a harsh algae scrapper for these types of tanks.

Depending on how much algae you removed, there might be some algae floating around in your tank. Try and take out as much as you can, and you may want to use the siphon again to catch some of the stuff on the bottom.

Step 5: Wash off your decoration

Once your tank is free of algae, you can deal with your tank decorations. They likely have algae and other waste products on them. You can try wiping off the decorations with your algae pad. If you have an unused toothbrush this also works.

Alternatively, you can use your gravel vacuum. One thing to remember though, never use soap when cleaning objects that will go back in your tank. Soap remnants are not safe for your fish.

Some decorations are hard to clean. You can soak them in warm water but do not use cleaning products. If you want you can add some bleach to your water. Use around a fourth of a cup. Afterward, rinse your decoration thoroughly. You can also put a water conditioner on them as well. Some decorations might be better off air drying but use your own discretion.

The cleaner you keep your tank, the less often you will have to clean your decorations.  

Step 6: Clean out your filter

Filters are another part of your tank that will need to be cleaned. How you clean your filter will depend on the type of device you have. Mechanical filters should be cleaned out once every month. Take their sponge or foam pad out to get this done.

It’s very important to clean your filter as it catches a lot of debris in the water. However, it does not remove it from the water column and can therefore still be a source of nitrates or ammonia.

The timing is crucial though. You don’t want to change or clean a sponge when you are doing a water change. The best time to do this is a week or two after your water change. This way, your fish will experience less shock and stress.

care for the aquarium filter in a freshwater aquarium. Cleaning and rinsing

Whenever you are cleaning a filter, you don’t want to run it under tap water. It’s best to use water from your tank. This ensures that the beneficial bacteria colonies you have grown will survive. Don’t clean it under the tap. Get the dirt and debris out of your filter and put your pad or sponge back in. It should not look brand new!!!

If you have a chemical filter, you’ll need to change it more often. After three to four weeks replace the cartridge. This is good to do during your water change. Some tanks get very cloudy and dirty when they have a bigger bio-load. So If your tank water has more waste and looks murky, try changing the water and your filter more often.

The reason for this is because chemical filtration relies on active carbon, which looses its power over time.

Biological filters require the least amount of maintenance. You don’t need to clean it out too often. But if you do wash it with water from your tank. Again, you want to keep your bacteria colonies alive. So put everything back into your tank as soon as you wash it.

Step 7: Put water back into the tank

One of the final steps in this process is replacing the water you took out of your tank. How you go about preparing water will depend on your type of tank. Saltwater and freshwater tank preparation is drastically different. So I will go over the basics of both for you.

Freshwater aquarium water preparation

When you add fresh water in you want your water to be in the right conditions. The water should be treated and at an appropriate temperature. A thermometer will make sure your water is right for your fish. Know the exact temperature needs of your fish and make sure it is at that range. This is important for your fish’s health. When your water is at the right conditions you can carefully pour it in.

To prepare your freshwater aquarium water, you can follow these steps below:

1. Get a clean container or bucket and get your water.

2. Condition the water so that chlorine, toxins and other substances are not present in the water. Some conditioners can even get rid of ammonia so be on the lookout for those. More information on this can be found in this article I have written previously.

3. Don’t perform a water change on a whim. The best thing to do is to prepare your water the night before. Put your water in a bucket and condition it overnight. 

4. Also, the water must be close to or at a similar temperature to your tank. Use the thermometer on your tank and your new water. You don’t want it to be too different this could stress your fish out. Using your hands to feel the temperature difference is also very possible.

5. Lastly, check the conditions of your water before you put water in it. If it has a lot of nitrates you can use reverse osmosis water. Alternatively, a freshwater aquarium buffer can also lower nitrates in your tank.

6. You don’t want to overfill your tank. Water should go in gently and not spill over the tank. I always use a siphon to slowly pour in my new water, to not stir up the substrate on the bottom of my aquarium.

Saltwater aquarium water preparation

Saltwater preparation is different from freshwater preparation. There are a few extra steps to consider when changing the water for a marine aquarium. You want the best quality water for your tank. To get your water where it needs to be, get a good synthetic salt mix. 

Saltwater fish are also more sensitive to water changes than freshwater fish. Make sure your water is at the right condition before it goes in. It needs a certain level of salinity, a certain temperature, and a certain ph. All these things should be in check before you let your prepared water mix with your tank. 

To do this, you will need to prepare your saltwater the night before. Do not use tap water for this process. Get a bucket, your salt mix, and some purified water ready:

1. The first thing to do is to put your water in a clean bucket.

2. After the water is in, you’ll want to heat it up. Most salt mixes need to go in warm water. A heater device can be bought at your pet store if you don’t have one.

3. Next, put the salt mix in your water. Salt mixes can also be bought at your pet store. Make sure to follow the instructions. You don’t want to add too much salt into your water. You want the perfect mixture. Usually, you should put half a cup of mix for every gallon of tank water.

Use a powerhead to mix the salt in.

4. Let the mix sit overnight so it can aerate and so the salt can dissolve completely.

5. The next day, you want to check your mix to make sure it matches the conditions of your tank. Check the level of salinity in your water, a salt probe will help you do this. Most saltwater tanks should have a salinity level of 30 g/L. But if you have corals or other inhabitants you might need to have a salinity of at least 35 g/L. 6.

Once the salinity is right, check the temperature and pH. You can use a water test kit to check pH and ammonia levels as well. A thermometer should be used to ensure that the water is warm enough. Most saltwater tank setups should be between 72 and 85 degrees Fahrenheit. This depends on your specific tank setup though. 

At this point you should turn all the equipment of the aquarium back on.

Step 8: Monitor the aquarium

It is very important to closely monitor the fish in the aquarium over the next couple of hours. Their behavior can tell you a lot about the quality of the water you have added to the tank. The aquarium will look dirty and will need a couple of hours to fully clear up. Make sure you turn on the filter, lights, thermometer and all other equipment you have running.

Step 9: Clean the outside of the aquarium

If your water is in good condition, there is one last step to complete! You want every part of your tank to look good. Get your cloth and some warm water and gently wipe the surface of your tank. You can also wipe down your lights and tank hood. Wiper fluid can be used during this step, but do not get any of it in your tank water! 

If you have an acrylic tank, make sure your cloth is soft. Also, consider getting polish for your tank to keep it from getting scratched or damaged.

Bart Sprenkels

I have been keeping multiple aquariums since I was 18 years old. Just like many of you, I started with two goldfish but quickly learned they were not suitable for aquariums. Later, I switched to a tropical community tank and I also have two pet musk-turtles in a bigger aquarium. You can read more about me here.

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