Just got home, what a long day! Everything is alive and well. The skimmer did not overflow, the pumps didn't come off, and the powerheads didn't start a vortex, my huge snail didn't reek too much havoc and my apartment did not burn to the ground or flood the one below!
I've been gone for just about a week, so here's what I did:
1. Skimmed dryer than usual so the collection cup wouldn't overflow
2. Did a 20% water change before I left
3. Ran a new batch of carbon
4. Filled the tank to the brim at a slightly lower SG than normal (1.024, normally 1.026).
5. Fed the fish as normal. I usually only feed them twice a week, so I figured they'd be fine going without for a few extra days. I know that I've gone for more than a week (eg exam weeks) without topping off or buffering and adding Ca, so I knew that should be fine. My only worry, really, was something falling over or the mag3 coming off my skimmer.
I actually have a funny order of easing myself into checking out the tank (based on experience).
First, my building was still there. Second, I could see my lights from the street. Third, my downstairs neighbor did not leave a note saying "you're flooding my apartment!". Fourth, I stand at the stairs in my apartment and listen to the water. Is it too loud? (the day the pump came off it was way loud, i could hear the splashing). Fifth, I get the far away view of the tank to see that general structure is ok. Sixth, I wait to see one a damsel flash across the tank, and finally, I examine closely to make sure everyone is there
