That is from a south african forum that I am on where I heard about it. Just google rooibos in aquariums and you will find a few threads.
Rooibos ( /ˈrɔɪbɒs/ roy-bos; Afrikaans for "red bush"; scientific name Aspalathus linearis) is a broom-like member of the legume family of plants growing in South Africa's fynbos.
The generic name comes from the plant Calicotome villosa, aspalathos in Greek. This plant has very similar growth and flowers to the redbush. The specific name linearis comes from the plant's linear growing structure and needle-like leaves.
The plant is used to make a herbal tea called rooibos tea, bush tea (esp. Southern Africa), redbush tea (esp. UK), South African red tea, or red tea. The product has been popular in Southern Africa for generations and is now consumed in many countries.
Rooibos is becoming more popular in Western countries, particularly among health-conscious consumers, due to its high level of antioxidants such as aspalathin and notho***in, its lack of caffeine, and its low tannin levels compared to fully oxidized black tea or unoxidized green tea leaves. Rooibos also contains a number of phenolic compounds, including flavanols, flavones, flavanones, and dihydrochalcones.
Rooibos is purported to assist with nervous tension, allergies and digestive problems.
Traditional medicinal uses of rooibos in South Africa include alleviating infantile colic, allergies, asthma and dermatological problems.
Although human studies of rooibos are scarce in scientific literature, animal studies suggest it has potent antioxidant, immune-modulating and chemopreventive effects. In addition, rooibos tea has not been found to have any adverse effects.
It is often claimed that "Green" rooibos (see above) has a higher antioxidant capacity than fully oxidized rooibos. However, one study, using two different ways of measuring antioxidant activity, found conflicting data, with green rooibos showing more activity under one measure, and less activity using the other. The study also found conflicting data when comparing both forms of rooibos to black, green, and oolong tea, although it consistently found both forms to have less activity than green tea.
In 2010, eleven poison dart frogs were raised at WWT Slimbridge by amphibian keepers in pint glasses of water, topped up with shop-bought Rooibos tea. Rooibos was used because it contains antioxidants with anti-fungal properties. This successfully protected the frogs against infection by chytridiomycosis.
A recent study performed by Japanese scientists also suggests that Rooibos tea is beneficial in the topical treatment of acne. This is due to levels of alpha hydroxy acid, zinc and superoxide dismutase present in the herb.
And from the little googling that i have done i also just found out its a good way to treat a tank with algae.