Positive line test, negative digital.

So I got my faint BFP this morning and i’ve taken about 20 tests that have all come back with the same line 🙈🤷🏼‍♀️ so I know its not a fluke evap or something, but just went out and bought a digital that says negative. How much HCG is needed to turn a digital positive? I think I’m 10 DPO.