In our hobby, waste lines (from dt to sump) do not need primer. As
@jmc1974 wrote, you can easily clean the ends with iso-alcohol and be good. You can also do a light sand to the end, and only use glue. I am obsessive and used purple primer....Only because it came in a pack with glue. I measured each piece and kept the purple back from the farthest point of the bell of the fitting, so that when I glued, the purple stayed under the fitting. It makes a nice purple ring right to the edge of the fitting if done this way, but takes way more time than just slopping it on.
In the real world where work is viewed by an inspector, the primer is purple so that that individual can see and know that joints were done to spec and approve it. NEVER EVER use clear primer on a project UNLESS the inspector knows and approves prior to your first joint.....There have been entire projects that have been ruined because of this oversight....The solution to that is removal of all glued joints, lots of couplings and lots of extra fittings. IT does not matter if the client does not want to see purple primer. They don't like to see change-order bills either when they need 300% more fittings.
However, keep in mind that no building permit is required or necessary for piping out a fish tank.
I would ALWAYS recommend using primer on the supply line from the return pump(s).