How to Clean an Old Dirty Fish Tank Safely

The salt water aquarium hobby can be very expensive. Especially when you are trying to start a new set up. We all try to cut corners to save a few bucks. Sometimes the most inexpensive route to find a used set up.

Here are some ways to find a used set up or used aquarium equipment:

How to Find Used Aquarium Equipment

Most of the time when you come across a used set up, it has been sitting in someone’s garage or storage unit for sometime. It more than likely has accumulated dirt, dust and other nasty yucky stuff. If the tank was not cleaned out properly before being stored, it can be an even greater hassle to get the tank ready for new live stock. So what is the most efficient and safest way to clean out an old aquarium?


I swear by it. You can consume it yourself (though I wouldn’t recommend it) and it is not harsh to your aquarium. It is also easy to rinse.

I recently picked up a used 37 gallon all in one cube tank. I purchased this tank to be set up as a frag tank next to my 90 gallon display tank. It’s hard trying to control the whereabouts of your smaller corals when you have huge hermits that may knock them down or in my case, a pesky sand sifting goby who likes to bury them.


When purchasing a used tank, I always fill it with tap water and let the equipment run for a few days to make sure the tank does leak or have any other problems. Trust me, save yourself the time and headache by doing this FIRST. I know when we all get new tanks, we are so excited to set them up and get them going right away. Always, Always, Always give used equipment a test run before setting up permanently.

After I determine that the tank is ready for setup, I put a couple of cups of white vinegar in the tap water already running in the tank. I allowed the tank to run with the vinegar and water solution for about a week. On the 7th day, the crystal clear water that was in the tank turned to a dark, black cloudy looking water. I had no idea what was happening. Quite frankly, I started to worry. After speaking to some trusted experienced reefers, we determined that the vinegar was pulling all of the nasty stuff that had been sitting in the equipment and in the tank itself. It just amazed me that it took a week to do it.

I emptied the water out of the tank, scrubbed the sticky black stuff junk off of the glass and all my equipment and rinsed everything very well. I actually used one of the pads that is normally used for filtration. Since I will replace all pads that were previously running in the tank, why not put it to good use by cleaning with it.


After rinsing, I filled the tank back up with tap water and ran all the equipment to make sure that all of the debris as well as the vinegar was completely rinsed. Running the tank on this “rinse cycle” for a few days will give me the peace of mind that I need to know my tank is as good as new.


After a few days, I will add sand, old salt water from my 90 gallon display tank (water change time), along with some new salt water and a few pieces of live rock from my 90 gallon display tank.

Stay tuned…A link will be added to this post in a week or so.

Happy Reefing!

Comment below: How do you clean your tank?


4 thoughts on “How to Clean an Old Dirty Fish Tank Safely

  1. Love this method, i am going to set up an old tank for my son for Christmas, but the tank has spent a few years in the garage. Can’t wait to start cleaning it.

  2. I lost power over the summer and my saltwater tank crashed., After recovering from the storm we could never get the tank back to anything good. It started to smell and I thought everything was lost and dead. As I have finally given up and am taking it apart I am finding some life and plan to restart in another tank. How do I clean the sand? I plan to sift all the gunk and dead stuff out with a net. ( catching the debris while the sand sifts through.
    My story leads to my question. How do I ‘clean’ the sand? Should I let it dry out completely before reuse? I have the unsalvageable rocks and ruble soaking in a peroxide solution. Can I use peroxide to clean the sand from all the slim and algae? The sand smells like death, but I plan to keep for my own reasons.
    Any ideas or advice is GREATLY appreciated.

    Thank you,

What do you think?

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s