And once this thread is brought up I guess I should respond to Patur aval assur.
They are chemically identical in color. but the chemical that comes from the Murux has a stronger cleavage and will stay on stronger. THe kla ilan should be easier to wash off. Now the gemara gives us a test that should make the kla ilan should come off. But it doesn’t. So this is not a question on the techeiles but a question on kla ilan. But what i am prooving from the bleach is that there still is a chiluk between kla ilan and the murex in the strenth of the dye.