Sounds like you bought some fem seeds from a breeder who fucked up. Dont use the seeds the hermie produces and try Herbies or dr greenthumb for future seeds. Dont order seeds from Holland or they will be confiscated at the border.
You dont need to adjust ph for cloning as they are not consuming nutes just water. Also if using rw cubes make sure the cube is never much more than 50% wet after watering and sterilize your tools.
Plant them just before you leave, drench the medium and put them under a small cfl in a dome., they should be sprouted when you get back and need a watering.
Try yellow strips hanging and pieces cut up and places onto the medium takes about a month
If that fails try pantyhose tied around the whole pot and around the stem to trap them in
if that fails try this residual insecticide it will work by killing all gnat larvae in the rootmass.
It doesnt like the medium and its starving, ever considered feeding it bro? the medium would have almost nothing in it and its now def in N,K Mg and Ca just to name a few.