How can I locate an inground pool leak?
Your leak rate seems to be too slow for the dye tracing method you describe.
You should place temporary patches over any suspect locations and observe which patch gets tightened by water pressure.
Almost any watertight flexible membrane and temporary watertight attachment will do. I would use cut-up garbage bags and duct tape. It only has to last for 24 hours or so.
Be sure to trap a lot of water under each patch when you apply it. The next day, you will find the patch covering the leak has been flattened like a vacuum pack while all the other patches are still blobbing about like happy octopi.