Can I put a little baking soda in my TT toilet?

I just bought a used TT in September and had the same issue.
Had water in the bowl to keep a good seal, put in chemicals into tank with some water. Cleaned all over bathroom... still had smell.
Got a flashlight out to look for the poo mound and instead, found a piece of poo below the seal and above the tank in the bottom half of the toilet that was stuck on the "wall" of the funnel into the tank.
A toilet brush and a little scrubbing and no more smell!!!

good luck and congratz on the new trailer!