No rubber. I have put in some plastic covers we get extra which we otherwise dispose as trash [so many of them come in to the house in spite of rejecting many!] and then put the liner. The plastic covers are just as a hope to divert the root tips. But they do not guarantee. The roots are only in the side, one side especially. I know it must be from a tree in the neighbour's yard about 50 feet away. They must have come through the brick basement of the compound or less likely to be from the hibiscus tree which is there for 20+ years, very close to the pond. The bigger holes are at the top 6 inches and I see more of the tiny piercings a foot below on the side also - but I have left it like that. If I remove the root, there will be the hole. If the root stays there, it will hold water reasonably longer. I really do not know when I will get the urge to replace the liner.
