I had a question about light timing

So if I want 18 hours on and 6 off this is how I would do it correct? Or would I have to make two timings. 1 from 10:00pm to 11:59pm and the 2nd from 00:00am to 4:00pm?

Also, I’m doing hydroponics I have a deep water culture bucket with an air pump that needs to be running 24/7. I have the pump on the water outlet.

This is an example of how I would try to make it run 24/7 every day but I’m not sure if this is correct. Is there a different way to make my air pump ( irrigation ) run 24/7?

Any help for both my question would be very helpful thanks.

I run mine from 4pm to 10am as a single light cycle. No problem with the day changeover at midnight.

As far as the pump, I run mine(air and water for rdwc) through a different power strip since they run 24/7.