Safety concerns. Always marinate meat and fish in the refrigerator. You can use some of the marinade for basting after removing the meat or fish from it only if you bring the marinade to a boil and cook for five minutes to kill any bacteria.
Running the pump at night should only be when you are doing a major chemical treatment such as algae clean-up. Your pool is more vulnerable during the day, plants don't grow at night the way they do during the day--that's true of ALL plants including Algae.
Another user said: If by the pool filter, you mean how long to run the pool pump to circulate water, I have been advised by pool pros to run it according to the hours of daylight at the time. e.g., in the summer run it 12 to 14 hours and in the winter, 8 hours.