One minute on 3 minutes off was what I had on my old boat. Kept fish and bait alive with no problem in 22 gallon well.
I think tank volume can a lot to do with how long it should run. Bigger volume less time, more lag.
Smaller tank more time less lag. Good idea to have it programmable so you can adjust for conditions.
Infidel and proud of it.
From Genesis: "And God promised men that good and obedient wives would be found in all corners of the earth."
Then He made the earth round...and He laughed and laughed and laughed!