The size of pump you need for a 30,000 gallon pool is a minimum of 42 gallon per minute flow rate although a 52 gallon per minute flow rate pool pump is best for the 30,000 gallon pool.
You can run your pool pump 12 hours a day as pool pumps should run 10 hours to 12 hours a day during the summer to keep the water fresh and clean.
In winter if you have a pool that you use in winter the pool pump only needs to run 6 hours to 8 hours a day.
Running the pool pump longer will not do any harm and will keep the water circulating to prevent algae buildup in the pool.
In the summer algae grow more in warm temperature so the pool pump needs to run more often than in cooler weather.
I run my pool pump 12 hours a day and then let it rest for a few hours and then I let it run again all night to keep the water circulating.
While you don't really have to let the pool pump run all night it won't hurt anything and the cost on my electric bill is minimal.
Running the pool pump during the hottest parts of the day helps to combat the effects of the sun, especially with deterring algae growth and removing bacteria and debris during peak swim times.
Splitting up the run time for the pool pump into shorter intervals and running the pool pump during the morning as well as in the evening can help to maximize efficiency.
Some pool pumps use a lot of electricity while others use less.
A pool pump should also run when people are swimming to keep the water circulating and clean.
Even commercial public swimming pools keep their pool pumps running when people are in the pool.