How can I prevent mold in the tape?
You can prevent mold from forming in the tape by coating the sail.
With some sails, the tape used darkens over time. This is due to fungus. Dirty water with traces of fungi, algae, etc. can get between the layers of the tarpaulin through the stitching holes. Over time, the tape will become moldy and if you are unlucky, you will also get mold between the laminate with a laminate tarpaulin.
You can prevent this yourself by coating a tarpaulin. By closing the stitching holes in this way.