Hi Strat-Mangler,
There is more about the different types of foundations that are suitable for different types of mattresses in the foundation post here. It’s normally a good idea to check with the manufacturer to make sure that any foundation you are considering will be suitable for your specific mattress because they can each have different requirements (some mattresses do best with a more flexible box spring with springs inside it and some do best with a rigid non flexing foundation) … but having said that … the Triton will probably be fine.
I would first try your mattress on the floor though to confirm that a firm and evenly supportive surface will the solve the sagging issues and that they are only in the foundation and not in the mattress itself because depending on the type of mattress you have it’s possible that there could be some damage or sagging in the mattress as well.
Phoenix