I’ve ran a 40g with sump at my old house. Since we were not doing the grass maintenance the chemicals were never a concern, temperature during the cold season was handled with two heaters, it was no issues, corals and fish were fine, the hot season was maintained with a chiller, and it was hot, as well as very cold but heaters and chiller did an excellent job, BUT, one thing you’ve to take in the game too, moisture, you’ll play with a lot of moisture, both seasons, all the time, you might don’t feel it, but believe me, you’ll see it, specially if you have something made of steel, anything will get a coat of moisture and eventually you’ll see some of those things with corrosion, oxide.
I was able to just run the two seasons and not much of my other equipment, tools, this and that get damaged by corrosion but I was able to caught that and corrected on time.