If you have tubeless beach wheels that are leaking or you can't get the tire to seal to the wheel, try adding a sealant made for tubeless mountain bike tires.
I've changed a lot of tires, that sh!t is straight up nasty to deal with, and it doesn't really work that well in the first place. It will eventually leak again. And I really don't care if it worked for you, you're an anomaly.
Put a tube in, the tires are soft as hell, and easy to get off of a rim, or go somewhere and pay them $4 to put the tube in. You don't even have to pull the tire off, just break the bead on both sides, get the tube in. I think I broke the bead on mine with my foot.
This isn't a high stress application. Cat-trax have a strange tire size, and its tough to get a tube that is the right size. The tire is a 21x12x8, I think both of mine have a 22x12x8 tube in them. You aren't putting any load on them, and the chance of the tube pinching itself and leaking is pretty low. I threw tubes in close to three years ago, and I don't think I've added air since then.
