Can I give 3 day notice to tenant who is thousands behind even though old manager was taking payments?

You absolutely need to follow the terms of the lease, which we assume is in writing. Every lease is different, but generally there is a clause that says when a tenant is late/in arrears, and even where that is deemed a default, there is usually specific language on how to deal with that particular default and the notice requirements. Typically at least 5 or 10 days WRITTEN notice with a right for them to cure that type of default before you can just oust them. But again, it depends on the contract. You should consult an attorney to review that for you.