Without knowing your short or long term goals.
I have seen investors struggle with this heavily. I can tell you the longer you wait the more weird and difficult it gets. And you will lose cash flow.
If 30 units are under by $200, you are under GRI of $36,000 in the first 6 months. We have had investors offer cash for keys, an incentive for them to move for maybe $900 each. Here is how it looks. "Dear tenant, this property is going in a new direction from ownership and we are offering $900 to assist with your moving costs if you agree to move within the first 30 days." Something like that.
I think you will have takers on that. For those units you will break even or increase income in the first 6 months. You helped them, and got the unit back and cash flow closer to your goals.
From that initial offering of C4Ks you will find out who is going to be easy to transition and who is not. Bottom line, I would not wait on this. I've seen a lot of owners get deer in the headlights with the tenant moving thing. It's not the most glamorous part of this business but if done correctly everyone can benefit.