Hi Scott and welcome to the forum
What sort of African cichlids do you keep, Rift Lake cichlids or river cichlids?
The Rift Lake cichlids like and need hard water with a high pH. If you have these types of fish, you don't want to use a water softener on their water.
If you have river cichlids from soft acid water, they need soft water but most water softeners use an ion exchange resin and swap the calcium for sodium. Sodium is bad for soft water fishes and can cause kidney damage.
What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website (Water Analysis Report) or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).
Rift Lake cichlids from Lake Victoria need a GH around 300ppm, fish from Lake Malawi need a GH around 350ppm, and fish from Lake Tanganyika need a GH around 400ppm.
If you have cichlids form soft water rivers, they usually come from water with a GH below 100ppm.
--------------------
How often do you do water changes and how much do you change?
Do you have a light unit above the aquarium?
If yes, how long is it on for each day?
Do you have any live aquatic plants in the aquarium?
Do you add aquarium plant fertiliser to the aquarium?
--------------------
Soft water does not encourage algae, neither does hard water. Algae grows in any water where there is light and nutrients. If you have lots of live aquatic plants in the tank, they reduce the amount of algae that can grow. If you don't have any live plants in the tank, and the aquarium gets some light, then algae will grow.
Lots of nutrients also contribute to algae growth. This can normally be dealt with by doing big weekly water changes and gravel cleaning the substrate. Regular filter cleaning can also help reduce nutrients in the water.