Help with my tank plumbing diagram

[sphelps]

I don't think you should tie the drain line from the tank upstairs into the line from the basement tank. Since the basement has a herbie, teeing the other tank line into the primary line of the herbie will cause issues, especially being that it's coming from another floor. Also can you not run two lines from the upstairs tank for a herbie overflow as well? It's going to be noisy otherwise.