Hi, the tank looks great!
Yes, the algae will grow on the coral rocks. It looks great and also provides food for cichlids. In my tanganyikan setup I have corals to keep th PH up. My fish love them, but remember the Malawi and Tropheus are very active fish, so choose pieces with not sharp edges to avoid injury to fish. If you want to clean them bleach them on the sun for couple of days.
Some people use chemicals to clean the corals which is WRONG.
Good luck, can't wait to see "stereo" aquarium lol :happy2: