Yes, they’re not our usual ones but some special ones we received for clinical trials. They very conveniently happen to closely resemble some of the concrete water towers that you see from time to time.
It was serendipity that led me to add ABs turbines on top. Those are mounted on a 5/8″ washer which neatly fills the hole on the top of the pot. A unifying coat of paint on the components & voila!