Are you using the right carpet cleaning chemicals?
Here is a quick test to ensure you are using the most effective chemical on your carpets: Pour a small amount in a shallow dish. Set it aside and allow it to dry entirely. Later, check the dried product. If it is gummy or sticky, it is not beneficial for your carpet since after cleaning it will leave a residue. On the other hand, if the dried product is flaky or powdery it can be easily vacuumed up from your carpet fibers.