Tangled threads
I had similar problems of thread pools, particularly when I use embroidery thread.
I found that using a small hair band on the thread spool so that the thread has a bit of tension and can't fall off the spool has helped. I bought small hair bands at the dollar store - the ones that are a soft stretch, pastel colors. Be careful to find the ones that don't have the metal connector. (They also help with all those loose ends on spools not in use.)
Another remedy that I've used is to set a small beany baby on the thread at the leading end of the spool as the thread comes to the first thread guide. This also helps to control the natural pool of loose thread since it softens the jerking reaction of the thread going through the take up lever.
Either method has helped me to tame the problem of thread that falls off the spool and creating the pool.