How to Clean an Empty Fish Tank: Full guide and Tips

Written by Randy Martin

If you have a used dirty fish tank you will want to clean it up before putting it to use. I recently just cleaned an old fish tank and have done the process several times in the past. Here is what I found that works best while researching the process myself.

So the quick answer on how to clean an empty aquarium? Use water and vinegar to clean an empty aquarium. Scrub away hard spots with a brand new sponge. Do not use any household cleaners or soaps. A razor blade can be used to clean hard spots or to remove stickers, backgrounds etc. Make sure to always rinse your tank thoroughly after cleaning.

Basically cleaning your aquarium is just going to require some elbow grease. But there are some ways to make it a lot easier to make sure you safely remove glass spots and stains.

Cleaning an empty fish tank

Okay so you got your used tank, or even new tank, and you want to give it a good clean before setting it up. First off if the tank is a used tank you should let it have a period where it really dries out, this will kill off most diseases, bacteria, etc. that it may have once contained.

Also if the tank is used you should do a leak test. Fill the aquarium up with water and let it sit for at least 48hrs, but more is recommended; periodically check the seams for moistness or stress, bowing, or warping.

Items you need

  • Water
  • Vinegar
  • Brand new sponge

Additionally…

  • Razor blade / Glass cleaner blade
  • Spray bottle
  • Bucket
  • Salt
  • Bleach

Water

Make sure you got a good source of water. You can clean your tank next to a sink, in a bathtub, outside with a hose, or even just using a bucket of water.

Vinegar

Distilled white vinegar

Vinegar is an excellent cleaner for an aquarium. It helps remove hard water spots and algae and can even kill off different organisms like mold.

The vinegar is easily rinsed off with water after you have completed the cleaning.

I recommend distilled white vinegar for its clarity and also its cheap price.

Brand new sponge

New cleaning spnge

A sponge will be great for scrubbing off all those hard water spots. You should only use a new sponge so you don’t chance applying any soap to your tank or some other chemical based solution.

Step 1. Soak and scrub the tank with water

First get your entire tank wet, use a spray bottle to dampen the tank or splash water on it from a tub, bucket etc.

Then after your tank is good and soaked, use the sponge to wash the entire tank thoroughly. Really scrub out those hard spots on the glass and also hit your trim to clean it up as well.

A great tip I picked up from one of Rachel O’Leary’s videos (youtube channel), is to use salt if you need added abrasiveness to scrub away the gunk. Apply a good amount of salt to your sponge and use that to scrub. The salt won’t scratch acrylic or glass, and it is easily removed with a rinse.

You may also need to use a razor blade to get off the really hard calcium build up or any deeply crusted algae spots.

After this first wash and scrub, give your tank a quick rinse.

Step 2. Apply vinegar to soak and wash

At this point you can apply vinegar to the entire tank inside and out. You can mix a solution of half vinegar / half water into a spray bottle, and spray the entire tank and let it soak in for a minute or two.

Or alternatively you can pour the vinegar straight onto a piece of newspaper and use that as a wipe to wipe down the entire tank.

After you have applied the vinegar and let it soak momentarily, then you should do a further scrub and wipe with either the piece of newspaper or sponge getting rid of the rest of the spots and buildup.

Step 3. Rinse thoroughly

Now most tanks should be sparkling with just those few easy steps. To finish up you want to rinse your entire tank to wash away any of the vinegar and salt residue. Give it a few repeated rinses to make sure you got it all.

And voila! It’s like a brand new tank.

Washing with bleach  

There may be times that you want to wash your fish tank with bleach, like if you know the tank has had problems with infections and diseases, molds, all sorts of nasty stuff that you want to nuke away.

First be sure to wear rubber gloves when cleaning with bleach and work in a well ventilated area.

To use bleach for cleaning, pick a brand that is a standard plain bleach and mix 1 part of bleach to 9 parts of water.

Apply the bleach solution to the tank either with a spray bottle or a bucket and sponge.

Let the bleach soak the tank for approximately 5 minutes or longer, then do a deep scrub to clean off the gunk and white stains on the glass.

Rinse out the bleach very well and let it completely air dry. 

If needed you can then do the 3 steps listed above but make sure all the bleach has been cleaned out completely and any residue has been wiped out, so you don’t have any contact between the bleach and vinegar

Important: Never mix bleach with vinegar. The combination can release toxic vapors which can seriously burn your eyes and lungs.

Cleaning off stickers and backgrounds

Some of the used tanks you get might have stickers, paint, or backgrounds on them. To get them off use a razor blade or ideally a glass scraper. 

Just scrape off what you need to remove before doing the 3 main steps of the aquarium cleaning.

As I said earlier many people use a razor blade in cleaning the glass instead of a sponge. In that case just make sure the tank is wet before scraping away at the glass. But a razor blade is great way to get off these extremely tough and stubborn spots.

Related Questions

Vinegar to water ratio for cleaning aquarium? Mix 1 part of vinegar to 1 part of water. Mix the solution in a spray bottle for easy appliance. You can also mix the vinegar and water in a bucket to be applied with a new rag or sponge.

Can I use apple cider vinegar to clean fish tank? You can use apple cider vinegar to clean your fish tank. Be sure to rinse your aquarium very well before using it with your fish. Distilled white vinegar is more commonly used for cleaning as it is cheaper, and since it is clear, there is less risk of staining or residue. 

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