Raising Rent On a House-Hack?

[Lucas Hammer]

So I've had my 2-flat in Chicago for a little over a year and it's about time to raise the rent to get a little closer to market (will still be below, but we have a really good tenant). All of our communication is done through text or occasionally running into each other while going in or out. His lease is coming up, and due to some repairs and the fact that he's under market, we'll be raising it a small amount per month.

I'm trying to figure out the best way to position this without giving too much information and how to contact him. We never talk on the phone and just text each other if anything is needed and I don't know about mentioning it to him just on the way in or out of the building. The other thing I'm trying to figure out is how much info to give him. I'm not going to tell him details on how much we've spent on repairs (it's been a lot), but want him to know we're not just raising it for the hell of it.

I know this is a newbie question, but I couldn't find a specific suggestion for my personal situation. Thanks!