Previous Questions

    Latest Questions: Water Quality

  • How can I test the water in my aquarium?
    There are a number of water test kits and strips on the market (including King British 6 in 1 Water Test Strips) that are available from most good pet shops. We recommend that you regularly test the pH, ammonia (NH4), nitrite (NO2), and nitrate (NO3) levels and if possible, the dissolved oxygen (DO) level too. It is important that the ammonia and nitrite are at a very low concentration, and that the pH is stable. The nitrate level is less critical because it is not dangerous to fish unless at very high levels..
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  • What is Water Hardness?
    The ‘Hardness’ of water is a measure of the amount of calcium carbonate (CaCO3) in the water. The hardness of tap water depends largely where in the UK you live. Very generally, the South East, East Midlands and Anglian areas have hard water (200mg/L + CaCO3 / 12°dH). The South West, West Midlands, Wales and the North West has much softer water, due to the underlying bedrock of these areas. If you need to know the water hardness, ask your water supplier or use a hardness test kit. Hard water does no…
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  • What causes cloudy water in my aquarium?
    Cloudiness is usually caused by a bacterial bloom, which are usually harmless. Cloudiness is common in new aquariums. If your water is cloudy, then you should: ✔  Increase the aeration and make sure that the filter is working correctly.  ✔  Siphon the gravel and change a small amount of the water (15-20%) regularly until it goes away. Remember to add a de-chlorinator to the tap water. ✔  Test the water to make sure there is not an underlying problem.  ✔  Sometimes clo…
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  • Why does my aquarium water have a pale yellow tinge to it?
    This could be caused by a number of factors, however it is usually caused by leaching from aquarium gravel or bogwood in the aquarium. Make sure you wash any gravel and bogwood thoroughly before putting them into the water.  It can also be a sign of over feeding, so check you are not feeding too much. Always remove any uneaten food from the water, and maintain your aquarium regularly.
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  • Why are nitrite levels slowly creeping up in my new tank set up?
    What you are experiencing is very common. Your aquarium is still not 'mature', which means the filtration system has yet to establish a level of beneficial bacteria that are capable of consuming the nitrite in your tank. There are no 'set in stone' rules on how long it will take your aquarium to mature as there are so many factors that affect it. You can help the process by doing the following ✔  Manually increasing the number of bacteria in the filter using a commercial product such as King British …
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Most Frequently Asked

How often should I change my aquarium water?

Most aquariums should be cleaned every 2 weeks on average. It is easier to combine cleaning and water changes by using a gravel siphon, as this also removes any dirt and waste from the bottom of the tank.


When can I add new fish to my tank?

If you are introducing new fish to a matured aquarium, then there shouldn’t be a problem. However, you should monitor the ammonia and nitrite level for the few days following introduction as a precaution. Also, you should quarantine any new fish for at least 4 days in a separate tank before adding to your main tank. This will help to prevent spreading any diseases.

It is advisable to run a new tank with water only for at least 1 to 2 weeks before adding fish, to allow the filter to build up some beneficial bacteria. It helps to add King British Filter Aid + during this period to help the filter to mature. Fish produce ammonia through respiration, and release it into the water through their urine and across the gills. In a matured aquarium, the filter can remove the ammonia quickly before it causes any problems. However, in a new, un-matured aquarium the ammonia will linger and may build up and cause problems. If fish are added straight away to a new tank, then the ammonia they produce can poison them and they may die. Also, once you do start adding fish, they should be added slowly and gradually, not all at once. Spread it out over of a period of weeks by adding two or three fish at a time, to allow the filter to adjust to the larger load of ammonia and nitrite.

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