I, too, have been having squirrel problems. I purchased safflower seeds and the squirrels don't like the seeds. It took a few days for the birds to get used to them. The seeds are good for this time of year but was told to feed the birds sunflower seeds when the cold weather comes for the sunflower seeds have more nutrients.
It was too funny when I first filled the feeder with the safflower seeds. The birds and squirrels came right away for a feast. The squirrels smelled the seeds and immediately left the feeder. The birds were going round and round the feeder stopping at each hole looking for sunflower seeds. At first they would spit out the seeds but found that the seeds didn't taste that bad after all.