Some skimmers in hot tubs have a cartridge in the skimmer that is the filter for the hot tub.
Even though you have an external filter, the tub might have originally come with a cartridge in the skimmer.
Check for a cartridge and see if the skimmer is running dry while on high speed.
There are several types of weir. There's a sliding weir that goes up and down. There's a hinged weir that rotates up or down on a hinge. And there's a floating weir that is circular.
Any type of weir can stick and block the flow of water into the skimmer.
Try turning off the blower and run just the pump on high to see if the problem is the same.
Even though you have an external filter, the tub might have originally come with a cartridge in the skimmer.
Check for a cartridge and see if the skimmer is running dry while on high speed.
There are several types of weir. There's a sliding weir that goes up and down. There's a hinged weir that rotates up or down on a hinge. And there's a floating weir that is circular.
Any type of weir can stick and block the flow of water into the skimmer.
Try turning off the blower and run just the pump on high to see if the problem is the same.