What is the best shower stall caulk ?

We have a new trailer with a corner shower with the round glass doors.
They sit in an aluminum channel that sits on the plastic floor pan.
Evidently there was no sealant or caulk installed between the aluminum channel and the floor pan and there is water leaking (very bad) under them and coming out on the floor.

In the past in our various houses I have used regular white bath tub caulk. Would this be the best to use or are there newer and better caulks?

Please don't say take it back to the dealer. I don't want to hear that!

jack L