New Owner End of Season questions

Hey folks, looking for some advice. I bought a house with salt water pump, new system with auto filter speeds based on time of day. All season it was practically maintenance free once I got the levels right.

I knew I was closing uo soon so havent checked the chemicals in a few weeks. Today I backwashed with anticipation to close this week. Unfortunately this led to my water level being near the bottom of the skimmer. About an inch or so above causing powerful suction at the skimmer and likey air getting through.

I shut off the pump today to avoid taxing the system with too much air. Do I need to be concerned with the pool getting too dirty before closing? I do have a robio skimmer and vacuum so I guess I can just run those an brush the walls the day before?

Do I need to make sure chemical levels are right as well?

Appreciate the info.