The DIY co2 is also a major source for BBA, which in my experience, is the hardest algae to battle with. I've used DIY and finished with it after all sorts of algae came through, mainly the bba.
Use the pressurized system - it's better.

Excel does kill BBA if much overdosed (i've found it much higher than 1.5 times). It will also kill some of the plants as well...

Good fert regime (EI) and pressurized system will help you clean off the BBA in your tank.