For me its exciting watching my tank grow and fill in.
Nothing better than a tank full of thriving acros, mine or yours.
Im a low tech guy with no controllers but im home every day.
Probably the only guy running halides in my area, lol. I get alot of flak for it until they see my tanks.
I do love the Orphek light bars and run one and just purchased another for my 120.
I am also very excited about the advancement of leds in the hobby.
I could setup and run a thriving tank on the Orphek light bars alone.
Woo Hoo! I actually got really excited this evening! While cleaning out my DIY Rotating Algae Filter (which included the manual removal of 60 or 70 bristle worms) I came across two Peanut Worms. First time I've ever found them in my system. This won't ever happen to those of you not using real live rock from the ocean...
This is cool, I wanted to start a thread like this but found this one.
For me, it's really the science aspects. As a young punk I wanted to be a marine biologist but went into computer software instead. Much better living, but not nearly as interesting IMO. So learning about the biology and chemistry of these tanks is such fun. I love reading the longer articles about the various O-chem cycles, or about amino acids, for example. I used to buy every reefing book I could find, back when books were still a thing. Sprung and Delbeek, Walt Adey, et al.
Bit of background: I was in the hobby for a few years in the late 90s, then had to move. Now I'm trying to get back into it, and OMG how much has changed.
Back then, Berlin method was still being discussed daily on RC. Live rock from the ocean was the "best" way to go, so that's what I did. And I loved it. Sure, got a mantis shrimp (extremely interesting) and aiptasia (gonna happen anyway), but the amount of cryptic fauna and flora that came with that rock was AMAZING, and so much more interesting to endlessly watch than the coral, even the softies or LPS that waved in the current. Some of it was good, some bad, but all of it was so rewarding (to me) to research, identify, and try to figure out how to keep alive (which was nearly impossible 25 years ago). Now planning my new tank, and I'm kinda bummed that ocean rock isn't available anymore (I get why).
I'm blown away by the colors of all the coral nowadays. Doesn't look natural to me, or anything I ever saw exploring real ocean reefs, but that's fine. To each their own, aesthetically. But for me the short answer is biological complexity, how to keep it going, how to not break it.