Just make sure the tort is actually eating and if so then I would double check enclosure temps and keep an eye on her......if you want, you can offer longer soaks to possibly encourage a poo for you....
I soak her for about twenty minutes. I soak for about ten minutes and them I change the water and soak her again. I usually do this while I am preparing her food.
Once she is done soaking, I drain and clean the pan and I feed her in it. I see her eat so I know she is eating.
I would try a couple soaks more in the area of 30 minutes...and if you want to keep the water warm during the soaks you can do it outside during the warm day in the sun (making sure there is a smidge of shade if needed but primarily in the sun) or you can place a basking light over the soak dish....
However, if you know food is going in then it is likely it is also coming out---perhaps it is getting recycled for a second or third go round...