Can't user 5er again this winter - replace red goo in pipes?

joebedford wrote:
OP here:

My lines are PEX.

I'm aware that I should put some more in the P-traps etc.

I just don't know if the alcohol can get through PEX somehow.

You have already removed the water from the system. Water is what freezes. You have absolutely no reason to do anything else to the system. There is NOTHING in it to freeze.
lock the doors and forget about it. It is as safe now as it was last winter. Don't make this harder than it has to be.