Does anyone know a good memory cleaner? One expensive I was not anticipating with 32Gb of RAM.
Bingo. Best option is open terminal and do 'sudo purge'. But don't know if that will solve this particular problem.
I use an app called MenuBar Stats after having been a long time iStat Menus app guy. It seems that, at least for me, iStat Menus freezes up OFTEN, causing a number of other slowdowns with Finder and various other open apps. Since I've switched to MenuBar Stats, I haven't had any issues like that...

MenuBar Stats
MenuBar Stats 3, completely re-written, goes further than before. MenuBar Stats • A quick view to your system health right in your menu bar or/and Notification Center. • 7 advanced modules (Cpu, Memory, Network, Disk, Battery, GPU, Bluetooth). • 2 optional additional modules (Temperature...

It's my understanding that when 3rd Party apps like these offer an option to Free Memory, it's really just running a 'sudo purge' command anyway? Maybe I'm wrong. I've never had issues using a 3rd Party app to purge memory, though.