Aquarium guides

All guides

• pH and CO2 in the aquarium

  How to calculate aquarium CO2 from pH and KH: formula, CO2 chart and the safe range of 15–35 mg/l (ppm) for plants and fish.

• How to set up an aquarium step by step

  How to set up an aquarium from scratch: choosing the tank and spot, the equipment list, the order of setting up, cycling the water and adding fish safely.

• What temperature should an aquarium be

  The right aquarium temperature: 24–26 °C (75–79 °F) for most tropical fish. A chart for popular species, safe daily swings and what to do in a heatwave.

• Aquarium algae: causes and fixes

  What causes algae in an aquarium: too much light, unstable CO2 and unbalanced nutrients. How to identify the type of algae and remove it without chemicals.

• The aquarium nitrogen cycle

  The aquarium nitrogen cycle explained: ammonia, nitrite, nitrate. How long cycling takes, how to do a fishless cycle and how to tell it is finished.

• How often to change aquarium water

  Aquarium water changes: usually 20–30% once a week. How to match the amount to your stock and nitrate, how to prepare the water and which mistakes to avoid.

• Cloudy aquarium water

  Why is my aquarium water cloudy: white, grey, green or yellow. The cause of each kind of cloudiness and what to do to get clear water again.

• Ich: symptoms and treatment

  Ich in aquarium fish: what the white spots look like, why treatment continues after they disappear, how to raise the temperature safely and how to prevent it.

• Aquarium water hardness: KH and GH

  Aquarium water hardness: what GH and KH are, what popular fish prefer, how to lower or raise hardness and why low KH can make pH crash.

• How long should an aquarium light be on

  How many hours a day to run an aquarium light: 6–8 hours to start, up to 10 in a planted tank with CO2. How to set the lighting so plants grow and algae doesn't.