You have 75g with over 100w of light, and 10 hours photo period. Perfect condition for growing algae. Don't bother with DIY yeast CO2. The tank is too big. You would need 3 to 4 2l bottles of yeast CO2 to, maybe, provide enough CO2 level in the tank. The cost of the yeast won't kill you but the amount of sugar you need to buy would.
Right now, you can double or triple dose Excel. This should kill your BBA within 3 days. However, your plants may or may not melt from the Excel. I think your fish should be OK. Reduce you light period down to 8 or less hours. Go 2 bulbs instead of 4. For your CO2 substitute, try dosing excel daily instead. This arrangement would not promote your plants to grow fast.
The only way to promote your plants to grow fast with a lot of light is to using EI dosing and pressurized CO2.