Carpet should not really get dirt that quick, well unless they are mucky pups. Dust it with water and agitate then blot with a towel. If it foams there is a residue in there and needs rinsing with either acidic rinse or maybe water. When using a detergent with a high ph say 8-10 you will need to use an acidic rinse to stabilise either as an after spray which can be groomed in or as rinse in the solution tank. Some higher ph rinses claim to crystallise so they will vac away. Rinsing with plain water may also help, depends on ph. After cleaning just check the ph with a test strip try it on some samples. If i'm using powerburst for example I will rinse with clearwater rinse the cleaning work has already been done by the pre-spray. It's important to rinse thoroughly, some rush around and leave residue. I take my time, if i'm rushing i'm not charging enough.
In general I use DFC 105, 210 and microsplitters, unless I am doing black top. I have several repeat customers particularly schools and i've checked for residue and re-soiling and i've not found any.