Setting up your new Aquarium

Setting up your new aquarium

Setting up your new aquarium

New Tank Syndrome is the number 1 cause of fish death. If you take the time to read this and follow the steps, you will not have to deal with new tank syndrome, and you will create a healthy environment for your fish.

This article won’t deal with tank specifics- which tank to buy and what equipment to get etc. This will be covered elsewhere. These steps are for once you have everything you need- a tank, stand, filter, lights and heater (although the procedure is the same for coldwater tanks as well). Got all that? Fantastic!

When we set up a freshwater aquarium, our goal is to recreate as best we can the environment which fish live in out in the wild. It’s important to remember- most of the bodies of water that wild fish live in (lakes, rivers, ponds etc), have been around for hundreds, if not thousands or even millions of years. They are mature and stable environments, which in themselves are their own self- sufficient eco- systems. Your new tank is not- it is a sterile and man- made construction.

When you start reading up about water chemistry and all the different parameters and variables, it can seem so daunting that it’s easy to get overwhelmed, and very easy to just give up before you’ve even started. Don’t. There is one basic and fundamental process to understand, which, once you get your head around it, is at the core of maintaining a healthy environment for your fish. This process is the Nitrogen Cycle. Don’t worry- it’s really not that complex.

The Nitrogen Cycle

As we know, a brand new tank has nothing inside it. What keeps a tank healthy and safe is GOOD BACTERIA. This is the one most important aspect of your tank’s filtration- the good bacteria colonies. Our aim is to cultivate colonies of good bacteria within the filter of the tank, which will convert deadly toxins into something harmless.

There are three stages in the nitrogen cycle.

Note: Nitrite and Nitrate are two very different things.

1)      Ammonia stage. Fish produce waste, which is a source of ammonia. Ammonia is very toxic to fish, and can kill them very quickly. Ammonia is also produced from the decay of plant matter, and from uneaten food in the tank.


2)      Nitrite stage. Good bacteria number 1 (Nitrosomonas) converts ammonia into nitrite. Nitrite is also toxic to fish, and kills them.


3)      Nitrate stage. Good bacteria number 2 (Nitrobacter) converts nitrite into nitrate. Nitrate is much less toxic to fish, and is removed with each weekly water change.

Basically, fish produce ammonia in their waste. This ammonia would kill them, if it weren’t removed by our good bacteria number 1. Our good bacteria convert the ammonia into nitrite. The nitrite would also kill the fish, if it weren’t for our other friend, good bacteria number 2. He converts the nitrite into nitrate, which is only toxic to fish in very large quantities. Weekly water changes keep the nitrate level to a minimum, so it doesn’t become harmful.

So, as you can see- we need lots of good bacteria number 1 and number 2. As much as possible. Once we have loads of good bacteria 1 and 2 living in our tank, we will be ready for fish. So how do you create colonies of good bacteria in your tank? Through a method known as The Fishless Cycle.


The Fishless Cycle

These are the steps you need to follow to make your tank safe for fish. The purpose of the fishless cycle is to cultivate enough good bacteria, so that your tank can go through the nitrogen cycle. This will make it its own eco- system.

 Remember our friend good bacteria number 1? Remember what he eats? Ammonia. He needs ammonia in order to survive. So, the fishless cycle involves adding ammonia to your new tank, in order to feed the good bacteria, so it can multiply, until there are enough good bacteria to keep our fish healthy.

You will need:







Just google the names of the products- you’ll find them straight away. I’m not posting links as shopping websites are constantly changing. If you want mature filter media, you can make a thread on TFF and see if someone local to you has any spare. 

Got all those things? Read on.

Before you get anything wet, choose your substrate and ornaments etc. NOTE: Once you have laid your substrate down, you are stuck with it!! Think carefully and be patient. Make sure you clean your substrate thoroughly with water until the water runs clear, before you add it to your tank. Add the ornaments too, before you fill the tank with water.

Fill up your tank with water. Dechlorinate the water. Follow the dosing instructions on the bottle. Wait for the water to settle. Check your tank over for leaks. Once you’re satisfied it’s in a good condition, turn on the filter, and test the lights…

*Note: Adding aqueous ammonia can raise your pH. You should test your pH as well as everything else, just make sure it doesn’t go above 8.6- your cycle may stall if it does. Also, if you cannot find aqueous ammonia, you can also use Ammonium Sulphate or Ammonium Chloride. However dosing will be a bit of guesswork, and I recommend you use liquid ammonia if you can find it.

Now the fishless cycle begins.

1)      Turn your heater up to around 80 Fahrenheit/ 27 Celsius. This will help the cycle along. Make sure your filter provides good flow around the tank.  Work out how your filter works, how many sponges there are etc. If there is a carbon sponge in the filter, remove it. It will only slow you down.


2)      Test your tap water so you know what you’re dealing with. It won’t have ammonia or nitrites, but test it for nitrates, pH, and KH and GH if you can. If your tap has a very low pH, say lower than 6.6, you should read the note at the end of this article before you go on to step 3.


3)      You want to bring your tank ammonia level up to 4 PPM. You work out how much to add by using this calculator.

Jeyes Kleen Off ammonia is 9.5% so change that value on the ammonia calculator. Then adjust your required and existing PPM (existing PPM will be zero), to find how much ammonia to add.

Just remember to account for displacement. For example, if your tank is 125 litres, but you have ornaments in there, you probably only have around 100 litres of water in there.


4)      You should be testing your ammonia daily to ensure you’re adding the right amount. Once you’ve got it at 4 PPM, leave it there. Test it daily until you see it start to fall. As soon as it falls to 3 PPM, start adding more ammonia to keep the level at 4 PPM. Keep doing this, and start testing for nitrites.


5)      Keep testing ammonia and nitrites daily. As soon as the nitrites read above 0.25, reduce the amount of ammonia you are adding, so that you maintain the ammonia level at 2 PPM, instead of 4.


6)      Maintain the ammonia level at 2 PPM for about a week, while testing for nitrates. Your nitrates should start to rise.


7)      After about a week, do this: add enough ammonia to bring the tank ammonia level up to 2 PPM. Test both ammonia and nitrite. Make a note of the time. Test again 24 hours later. If both the ammonia and nitrite have fallen to zero within 24 hours, then bring the ammonia back up to 2 PPM and repeat the test the following day. Then finally, repeat the test for a third time, to ensure that the ammonia is really falling to zero within 24 hours.


8)      The day before you add any fish, do a very large (80%) water change (using dechlorinator of course). This is to remove the high nitrates. Then adjust your heater back down to an acceptable temperature (25). Add ammonia to bring the level back up to 1 PPM, so your bacteria don’t starve.


9)      The next day, test for ammonia, nitrite and nitrate. Ammonia and nitrite should be zero. Nitrate should be very low. If your readings are ok, you can now fully stock your tank.


10)   You’re finished! Well done for completing the fishless cycle. It’s still important to test daily for the first week after adding fish- especially for ammonia and nitrite. If for some reason you get a spike in either, do a 50% water change and keep doing this to keep the levels below 0.25.



*Note for low pH tanks- the cycle will stall if the pH drops too low. Just add a small amount of bicarbonate of soda to the tank (one teaspoon for every 50 litres of water), and this will bring your pH back up to an acceptable level.

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