should i add one more biotab?

High Diips, Yes, you can and should add another tab. I used to grow a lot with Biotabs and I always used an extra tab at the end of the growing phase. I never had an deficiency, next to that I did use the Orgatrex and Bactrex like you do so that is great. I never had to use the PK booster and the Cal-Mag but as long as you do not give too much then it is an nice addition to the living soil. Happy Growing Buddy! 💚