Every time I feed my fish I shut down my skimmer pump to prevent food from getting sucked into my skimmer. Unfortunately, sometimes I forget to restart the pump after the fish/corals are fed. My solution is to shut down the skimmer pump with time delay relay. In normal operation, the push-button switched is closed, the relay is in the normally open state (n.o.) (after the time delay), and the pump is running. Pressing the momentary switch causes the relay to shut off for the duration of the delay. I had all the parts on hand, so this project didn't cost me much. In my case, the delay is adjusted for about 13 minutes.

Cheers!

Deafboy