Charles East said "The spas in question are using pumps that create a significant amount of suction through the sock, and when the filter collects enough debris (hardly visible) the sock is now under such a strain that it is torn from the plastic collar and sucked into the pump. I service spas and have come across several of these spas that use the sock filter. While your sock appears to be the same size and design, I do not think the spa manufacturer designed the plumbing well... consider the pump is 2HP or higher, creating a significant amount of suction in the filter cavity. this only gets worse as the filter loads up. So far I have serviced the same spa 3 times in the last 6 months for the exact same failure (not with your filter) but with the more expensive "spa" ones that sell for as high as $50 a piece (not different from yours in appearance) other than the collar is blue. Frankly the folks who bought these tubs were sold some really badly designed spas.