There have been some cases where CMM does not support adequate growth of bloodstream-form T. brucei, and this is most likely due to the FCS. We used FCS Gold (PAA) previously because it is the most consistent between batches (although can still differ by country-of-origin). If you cannot access FCS Gold there are a few tricks that you can try to supplement the media whilst still providing a more biologically relevant medium than HMI9. 

Additions that have proved helpful in the past are:

100mcM of Phe, Trp,Tyr, Leu, Arg, Met (sometimes Phe and Trp are sufficient)

100mcM Hypoxanthine (or inosine)

If growth doesn't improve with all these additions then the next best option is to add 10% HMI9 to CMM. 

I hope this helps.

Darren