Calculate the volume of water in square, rectangular or cylindrical aquariums.

Calculation is based on an empty tank and is an estimate only.

Square or rectangular tank
Tank Length (in):
Tank Width (in):
Tank Depth (in):
Tank Volume: Gallons
Round or octagonal tank
Tank Diameter (in):
Tank Depth (in):
Tank Volume Gallons
Fish tank weight
Tank Capacity (gallons):
Fish tank weight approx: Lbs (plus substrate, rock and driftwood)

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Suggestions for setting up a tank. Consult a professional also before using this information.

The first thing to consider is the size of the tank; it’s common for people to think ‘oh I’ll just get a small one to start as it’ll be easy to look after’. Smaller tanks can actually take a lot more work than the big ones, because a small body of water is not very stable it will heat up and cool down quickly giving temperature fluctuations, any pollutants that get into the water will be heavily concentrated because there isn’t much water. A larger tank gives you more margins for error, and of course the more tank you have, the more fish you can have!

The conversion from US Gallons to litres is 3.7 litres to a US gallon by the way, UK gallons are 4.5 litres but in the fish keeping world we tend to work in the US gallons.

Setting up the tank

1. Choose the position for your tank, remove anything from this area and ensure the area is clean. I recommend you move furniture to ensure you have clear space around the tank to set it up.

2. If the tank is of a reasonable size and going upstairs or above a cellar then it’s advisable to put a sheet of ply or something similar on the floor under where the tank goes, this will spread the weight of the tank over as many joists as possible.

3. Put the stand in place and check with a spirit level if it is level. This doesn’t need to be millimetre accurate but if it’s significantly off then you should level it as much as possible.

4. This step can be skipped if you have a floating base tank. Put a layer of thin polystyrene on top of the stand, this levels out any lumps and bumps and can stop the tank from cracking. This is as important to a fish keeper as a towel is to an interstellar hitchhiker.

5. Put the tank on the stand, ensure it is sat squarely and there is no overhang. Again this is very important.

6. Hook up the equipment onto the tank, do not turn it on!

7. Wash your substrate thoroughly and put it in the bottom of the tank

8. Add dechlorinator to the tank and fill the tank with water to roughly three quarters full (I only say don’t fill it entirely because you’ll need to muck around in the tank a bit, if it’s full you’ll just make a mess of the floor, this is especially important if you do not have a forgiving wife/husband), switch the heater and the filter on. Depending on the make/model of the filter you may need to prime it to get it to start, there should be instructions with the filter.

9. When the heater and filter are working you can start to put your décor in, it’ll take a while for the tank to get up to temperature so feel free to muck around and take your time.

10. When you’ve done arranging the tank fill it completely up, you’ll notice that there are bubbles forming on the glass and the water may not be totally clear, don’t worry about this it should settle down within 24hrs or so. Put the thermometer into the tank.

11. I’d recommend running the tank for a day before starting your fishless cycle, if there are any problems with the equipment they’re likely to manifest fairly quickly, this gives you a chance to sort things out without worrying over your bacteria colony. Also you may need to tinker with the temperature a bit to get it right, remember trust the thermometer as your temperature reading and just adjust the temp up and down as needed.

Once you’ve gone through the fishless cycle you’ll be ready for fish and should have a fairly smooth ride of it for having done your prep work first.

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