Unless you are prepared to deal with his behavior and words because I’m sure this is only the beginning

The T&P valve nowadays ships with the new water heater units being installed so that failure point I think we just chalk up to Mother Fortune (as failure of that valve would precipitate behavior in your referenced video). 

But I highly doubt their behavior could have been unrelated coincidences.

If I don't like a certain behavior, they get a 30 day notice. 

Have you ever been shocked by the lifestyle and/or behavior of your tenants? 

I don't raise rent to reward good behavior, to reduce my costs, and to improve my rent revenue.

But by not responding, you're forcing tenants into exactly that behavior.

You have it in the lease that smoking inside of the unit or property is a violation of the lease and the tenant will be subject to damages.If they smoke on the back patio or outside it's not that big of a deal.The problem is when it gets cold outside they will smoke in the garage or crack the door to the outside while smoking inside.They will also crack the window to the bedroom hoping you won't notice.We do an inspection once a month.In the lease we can check at any time for maintenance issues.I don't keep the same time each month this way it keeps the tenants on their toes.When they know you can show up at any time it keeps them on their best behavior.

I saw a presentation by a collections guy once and he looked dead at the audience and said, "the best guide to future behavior is past behavior."

In part due to her behavior changes, I had to serve her 3-day notice.