I have some experience with Scenedesmus, BG11 is the most complete medium for this green algae, however if you supplement the medium with a carbon source such as acetate, glucose or CO2 you will get a growth booster.
If you just need to mantain the culture without taking care of productivity, BBM is fine too.
I am working with Scenedesmus sp. in BG-11N+ media, this alga is fast growing with BG-11 N+ media than BBM and F/2 media. You can use BG-11 media for your targeted algal sample.