Maybe you got a poor-quality hose. I also covered mine when new and I'm now at the 6-year mark with the same hose, no holes.
Here's something that might help your issue. If both of your toilets are macerators, just open your black tank and let it drain without turning on the SaniCon. It will drain in just a few minutes without running the SaniCon and putting that extra pressure on the hose. Open your grey if you normally close it while parked and let the grey rinse the hose, again, no pump, just gravity.
I also made my own sewer end. Using 1 1/4" pvc, I made a 3", 4" and 5" spinning hose end that threads into 90% of the sewer drains. This allows the hose to run almost wide open as the sewer end is about the same inside diameter as the hose.