Concrete catchment crack

[terracore]

A friend of mine had a concrete catchment tank under his house that was leaking through a crack. He patched it from inside with a concrete patch product, largely going by feel since it was dark and much of it was under the water line. He wasn't optimistic but it sealed the leak.

I would think in your scenario you would want to seal both sides of the crack, one to keep the water in and the other to keep the moss out.