Cichlids from East Africa’s Great Rift Valley are adapted to hard, alkaline water with a high pH in the wild, and should be given similar water conditions in the aquarium if they are to thrive. Tap water in the UK ranges from about pH 6-8.5 and depends on where you live, and where your local water authority sources its water from.
A pH of 6 is lovely for most South American and West African cichlids but is too low for Malawi and Tanganyika cichlids, which need it above 7.5 and for Tanganyikans, they really prefer a pH over 8. So if you keep Rift Valley cichlids but have tapwater with a low pH, you need to raise it.
But alkaline water goes hand-in-hand with hard water, so as well as needing a high pH, the ideal is to have a high pH, KH (or carbonate hardness,) and GH (General Hardness.) Here’s how.
Buffer the tap water
A dead-easy way to raise pH and hardness at the same time is to mix a buffer into your water. Coming in powder form, use as directed on the label and add to a bucket of water every time you perform a water change. It can also be added directly to the tank although it’s recommended that pH is raised slowly over time to avoid shocking the fish. Note also that ammonia becomes more toxic at a high pH, so ensure that filtration is working properly and is mature before doing so.