It sucks you still aren't getting longer use than that, especially since you're bringing in outside air. I think I'm going to use what media I have left and then try running the line outside without the scrubber and see what kind of difference I get. Even with getting 2 weeks or so each time I really don't want to have another expense if I don't have to.
I did have one other question. How long is the run for your outside line and did you notice any loss of air coming in to the skimmer? If I take my line outside I'm going through the floor where my apex cable runs from under the house. If I leave it just hanging under the house it will only be a few feet long, but if I run it completely out from under the house it will have to be another 20 feet or so longer. Not sure if that extra added distance will cause any loss of air coming in or not. Do you think there would be any benefit to making it completely outside, or will it be fine if the line just stays under the house?
I didn't cut the tubing at all after I bought it so the whole run is 10 feet I believe, the tank is only a few feet away from the wall I went through. I know there are people on R2R that have run them way longer. Think a lot of them used larger tubing and then stepped it down with a barbed fitting closer to the skimmer. With mine only being 10 feet, I noticed no loss of air that I can tell. Pump is not working any harder according to my Apex showing the watts used on that outlet. I'm sure if it was measured somehow it might be a small loss, but definitely not affecting anything. I did consider when the weather gets warmer redoing it with larger tubing and then going down to this size tubing right before the skimmer or scrubber (if I keep using it.) If you are getting outside air from having it under the house that should be fine.
https://www.reef2reef.com/threads/skimmer-ph-bump.248348/
That is where I got the idea for how I did mine outside, just added the compression nut and screen to the down tube. His tubing run was pretty long.