I could not fix my pool solar panel hole but I have a trick that I am going to use that work a long time ago for me. I fixed a broken fishing rod this way and a drain pipe this way with no tools other than what I had on hand. The first thing I need is a tube (straw), some Spider Wire Fishing line and some finger nail polish or acrylic paint.The stick to itself tape is as thin as a rubber band. The fire wire is fishing line. The brown tube is plastic or rubber.
I did not have to do this as I bought the proper size fitting (the video said 1/4 inch fitting), but this pool solar panel needs a 3/16 of an inch fitting. (solar video).