Great question! I find the tank relaxing, the fish shenanigans hilarious at times. My Tang gang drama is just funny. It never fails day after day. Three tangs battle for ownership of two tunnels in the rocks. They realize they can't guard both at the same time, so a new tang takes ownership of the second one, then the original tang switches tries to fight off the second tunnel, then they just keep exchanging places, flaring their fins, tails, and even going so far as to place themselves crosswise in the tunnels to block fish from swimming through. What's funnier is I have a dragon wrasse that lives in the sand under one of the tunnels. He comes out and fights all the tangs off...
So, does time watching, "As the tangs swap" count as tank time? heh. That said, I recently removed my skimmer due to over maintenance... I had pulled the whole thing to clean it thoroughly and couldn't get a union cap to loosen, ended up breaking the whole pipe of the skimmer. However, the side effect of this was simplifying my sump setup... I haven't put the skimmer back and haven't noticed only minimal negative consequences (on a 350 gallon system.). In fact some of my corals have since gotten more color and look healthier and are growing faster now. No algae outbreaks either!
The only negative outbreak is increased algae growth on the glass. That part is annoying. but, otherwise nothing else, My ATS seems to keep up with any increased nutrients. I'll take it!
I feed twice a day now instead of once before, I do more water changes. 2-3 times a week instead of once. Only 20 gallons at a time. Semi Manual AWC???
Monitoring Alk more than usual probably, but, that's about it. I find I spend more on stuff... This week ordered some bacteria supplements to see if I can get rid of some diatoms I have. Put more powerheads on the tank, and now with the skimmer gone I have more room in my sump to put in a filter sock or two, so, I am going to try to build custom filter sock holders to see if I can get that to work. Just constant tinkering to try to improve things. Probably make some things worse in the process.