Flex Seal repair on grey tank.

I've used goop on everything from my slide seal to shoes to motorcycle seats. Most of the time it's sold out at HD near me. 600 is often sold as a fabric mender and seems similar to goop.

If the tank is black abs I've also repaired with a kit found online. People use abs shavings and mixes that you can find on YouTube

Goops contribution to mankind is right in there with weedeaters, bungee cords and chainsaws.