How to Clean and Disinfect Used Aquariums and Accessories

How to Clean and Disinfect Used Aquariums and Accessories

The acquisition of used aquariums and accessories is fast becoming a norm in the hobby. Without a doubt, used aquariums and accessories are less expensive than new ones, hence aquarists that want to cut costs or save some extra cash are most likely to opt for used aquarium equipment.

Now, where the problem lies is getting these used aquarium and accessories ready for usage since it may be hard to tell whether the previous owner actually used it appropriately or if the equipment were properly cleaned before being put up for sale.

Regardless, the second-hand tank and accessories still need to be properly cleaned and disinfected to make it fit for usage. Of course, nobody would want to utilize a dirty tank to house fish, snails, shrimp, etc. considering the fact that they will be exposed to pathogens and contaminants in a dirty environment.

Meanwhile, if you have already acquired a used aquarium, the next course of action is cleaning it together with the accessories. For this exercise, you should not utilize popular cleaning agents like soap or detergent as these can be lethal to your fish due to their toxicity and the scent is particularly strong to get rid of.

Not to worry, we will discuss the ideal cleaning supplies for washing used tanks and accessories and the whole cleaning process, so continue reading.

Recommended Cleaning Supplies

Depending on your situation, you may not need all these tools and materials.

How to Clean and Disinfect Used Aquariums and Accessories - Recommended Cleaning SuppliesI will list them in the order of priority as I use them (some links to Amazon):

  • Bleach
  • Vinegar
  • Hydrogen peroxide
  • Water conditioner (to remove chlorine from tap water)
  • New soft sponges
  • Paper towels (or just newspaper)
  • Razor blade (Plastic blade for acrylic tanks)
  • Bristle brush
  • Algae scraper
  • Sieve
  • Salt
  • Soft cloth
  • Filter brush
  • Bucket (new bucket designated solely for aquarium use)

The Cleaning Process of Used Tanks

How to Clean and Disinfect Used Aquariums and Accessories - cat in dirty tankBefore you commence cleaning, take some time to observe the seams around the aquarium to make sure that they are not broken or punctured to prevent leaks when the aquarium is filled with water. If there are damages to the seams, you can use an aquarium sealant to fix them.
Tip for leaking test: To make sure that the tank is not damaged, you can put some paper underneath it and fill it with water for 1 day. If there are any problems this leaking test will detect them. If there are no wet spots on the paper you are good to go.

Next, take the aquarium to where you can wash it, preferably in a bathtub with a faucet that can be connected to a hose.

Using Chemicals

To clean a used aquarium, you will need bleach and/or vinegar.

Option #1: Pour a small amount of water and a capful of bleach or vinegar into the aquarium to make cleaning easier and eliminate the bad smells.

Option #2: Another way is to use a vinegar solution. Spray it on the walls, and let it sit for 10 – 20 minutes before cleaning with the sponge.

Then use a soft sponge to remove dirt and debris off the inner and outer surfaces of the aquarium.

It is important that you use a sponge that’s never been used before you do not want to add any residue into the tank. If there are some tough spots that are hard to remove, you can take some salt and apply it to the scrubby pad of the sponge. Do not worry; it is very easy to rinse out the salt.

In small tanks, you can just fill the tank with ten parts of hot water to one part bleach solution and wait for 30-60 minutes.

Important: DO NOT use soap! It is really hard to remove it completely. The oils within the soap are incredibly harmful to fish, shrimp, crabs, etc. gills. In addition, even traces of soap negatively affect fish’s slime layer.

If you did sodrain the tank completely, scrub it clean with hot water and start from scratch then rinse it again!

Limescale residue

How to Clean and Disinfect Used Aquariums and Accessories - dirty aquariumThere is often white residue on the walls of the old tank (limescale) caused by the evaporation of hard water, you can use a bristle brush, razor blade, or algae scraper to get rid of those.

Warning: While at it, try as much as possible to avoid cutting yourself or damaging the seams. Remember to use a plastic blade for acrylic tanks as a steel razor blade and abrasive sponges can easily scratch the surfaces.

However, if it appears not to be coming off easily, apply a pint of white vinegar or citric acid on a paper towel and let it sit on the affected areas to dissolve the limescale.

Wait for 20-30 minutes and scrub it off.

Rinsing the Tank

Rinse the tank with clear water till it’s thoroughly clean.

Now, take the tank to an open area and let it air dry completely so that the bleach breaks down into harmless compounds.  

Note: According to the manufacturer, the bleach solution is only good 24 hours, after that it starts breaking down mainly (95-98%) into salt, water, and oxygen.

Take a clean and dry piece of cloth to wipe down the glass of the tank and see if there are spots that need particular attention.

Tip: If you are satisfied with the result, wipe down the glass inside and outside with vinegar on a newspaper or paper towel. This little trick will help you to remove any streaking on the used aquarium.

Another great thing is that you should not worry that vinegar can harm your fish or shrimp. In the tank, diluted vinegar lowers the acidity (pH). However, you need to add about 1 mL of distilled white vinegar per gallon (4 liters) of tank water to initially reduce pH by about 0.3 units. 

Fill the old tank to the brim with tap water and observe closely to know if it is leaking. You need to be sure that you have not damaged it during cleaning.

Note: If you discover leaks in the tank, make use of an aquarium sealant (check the price on Amazon) to patch the leaks. You will have to remove the old sealant, clean the joints, apply your aquarium silicone on the inside of the tank, apply your aquarium silicone on the outside of the tank.


It is equally important to clean the filtration unit to remove accumulated dirt in the various components.

  • Start by disassembling the unit.
  • After that, soak the components in warm water for 10 minutes.
  • Clean the parts with a soft sponge to remove dirt and other impurities. You can use bleach or Hydrogen peroxide to make sure that they are absolutely clean. Hydrogen peroxide is commonly used as an oxidizer, bleaching agent, and antiseptic.
  • If there is limescale present on the filter casing— apply a bit of white vinegar and scrub it off using a bristle brush.
  • DO NOT reuse any old filter media. Throw it away. However, if you still want to clean the old sponge filter – soak the sponge in a water bleach solution and let it completely dry for a few days.

For the tubing, run water through them and push the filter brush through the insides and scrub off dirt therein.

You can also use the brush for other filter components with little space to get rid of trapped dirt particles. When you are through with that, rinse the components thoroughly with clean water and allow them to air-dry. Afterward, reassemble the parts and replace the filter media.

Plants & Decorations

The aquarium plants, rocks, and decorations need to be properly disinfected. For example, it can be a regular bleach solution to remove dirt and kill off algae and pathogens.

So, get a new bucket— intended for aquarium use only, don’t use a bucket meant for household purposes to prevent contamination with chemical residue from soap and detergents which are harmful to fish.

Make a 10% bleach solution and immerse the artificial plants, rocks, and ornaments for 15 minutes. Endeavor to scrub off stubborn dirt residue and stains with a scrubber, rinse the items in running water and allow them to dry to get rid of residual bleach. Do a smell test to ensure there is no chlorine smell, if any, rinse the plants and décor in dechlorinated water to remove it.

Live plants should spend lesser time in the bleach solution, say 1-2 minutes and a 5% bleach solution is often recommended.

Gently wipe off any algae patches and debris while in the bath and rinse the plants several times under running water. The next step is to pour water into the bucket, treat it with a water conditioner to neutralize chlorine, then rinse the live plants well before air-drying.

Warning: Be careful if you use bleach with porous items such as driftwood. The problem is that porous structure might be able to retain the bleach and leach in the tank afterward. That is why you have to wash it very well and leave the driftwood in bleach-free water for a few days. You need to be sure that any remnants of the bleach have dissipated.

For more information, you can also read “How to Quarantine and Disinfect Aquarium Plants”.

Aquarium Substrate

As with old filter media, personally, I would not reuse the old substrate in a new tank, especially sand. In my opinion, even after rinsing and cleaning used sand, it is not possible to eliminate all harmful pathogens that might be in it. The risk is too high and I cannot take it.

It is a little bit different story with gravel. We can clean it to get rid of any debris or dust that might have been accumulated on it.

How to Prepare Gravel

  • Place the gravel into a sieve or a
  • Rinse the gravel under running water.
  • Fill the bucket with ten parts of hot water to one part bleach solution and wait for 5-10 minutes.
  • Stir and move the gravel around (use a stick if necessary).
  • Next, the gravel should be rigorously washed. Let it dry for a few days before its usage.

How to Clean and Disinfect Used Aquariums and Accessories - boiling gravelIf the gravel has lots of clustered dirt, consider boiling it to help slough it off but this method shouldn’t be utilized for brightly colored gravel to avoid discoloration, the same applies to washing in a bleach solution.

In Conclusion

With more and more aquarists ditching their old aquariums and opting for larger ones, or selling aquariums they no longer need, it is now easy to find used ones in local fish stores being sold cheaply.

Keep in mind that thorough cleaning of the used aquarium & accessories is a necessity if your aim is to establish a healthy and safe environment for the inhabitants.

As you can see, the cleaning process is not really cumbersome. It doesn’t really take that much time but it’s worth the effort if you know the basics and have the necessary cleaning items to get the job done. Do it right, and your second-hand aquarium equipment will be as good as new.

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9 thoughts on “How to Clean and Disinfect Used Aquariums and Accessories

  1. This information was VERY helpful… I now have learned some mistakes I have made in the past and the consequences of those mistakes…
    Thank you so much!

    1. Hi Petra,
      You are welcome 🙂
      Best regards,

  2. Thanks so much! I knew I could not use a soap product. I did not know that bleach broke down so I will be using that.

    1. Hi Yvonne,
      Glad to help 🙂
      Best regards,

  3. Hi I have just got a dream tank it is 6ft long hight 2f 2 wide any help cleaning it as it took 4 men to carry it in to my liveing room

    1. Hi Mark Powell,
      Just wow!
      This aquarium is huge, to be honest it’s hard for me to suggest anything special for the procedure of its cleaning.
      If anybody has tips I am also all ears.
      Best regards,

    2. We acquired a huge tank and used a bleach/water solution to clean, then sucked everything out with a shop vac. Did a good rinse with r/o water and sucked it out with the shop vac again, wiped with cotton cloths and let sit for 3-4 days before starting set up. We now have a family of 9 healthy discus thriving.

  4. If I have old filter media like ceramic rings or ceramic balls, can those be disinfected? Or should they be thrown out? I was thinking of disinfecting them with my old gravel (using hot water and vinegar). I’m hesitant to use bleach because to my understanding, the ceramic balls are meant to be porous.
    Thank you for the rest of this information, it’s exactly what I was looking for! 🙏

    1. Hi Tania,
      It is important to note that ceramic rings serve as homes for beneficial bacteria in the aquarium. Therefore, deep cleaning can lead to the loss of these bacteria, which is the first consideration. Secondly, if you are unsure of the origin of these rings, it would be wise to discard them as their porous structure may contain undesirable substances. I would also like to mention that manufacturers of such rings often recommend periodic replacement.
      It is bettert to play safe here.
      Best regards,

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