Hi @Bel02,
Thank you for your question about repairing a hairline crack in your shower base.
As the crack does not appear to penetrate through the shower base, it doesn't pose a great risk in terms of failure of the shower base right now, but it is worth noting that this crack could worsen over time, so it is a good idea to keep an eye on it. If things get worse, you may have to look at replacing the shower base.
In the meantime, you can use this Rust-Oleum 13.3ml White Tub And Tile Touch Up Kit, which is a two-part epoxy acrylic solution that can be used for touching up and sealing cracks like this in high moisture environments.
Make sure you have a good read through the product specifications prior to carrying out your repair, especially the surface preparation steps.
Once mixed, you can apply the solution to the crack using a craft brush.
Let me know what you think, and if you have further questions, please don't hesitate to ask.
Jacob
