When my cat was having issues with wet stool, I switched him to a more expensive cat food. They eat less of it and it is easier for them to digest. Many of the low cost foods have too much fiber in them (which is why they are so much less expensive). This also helped with my cat's flatulence. I use Iam's here in the states, but most of the high-end foods will work. Be sure to make the switch gradually by adding a little of the new food to the old food and gradually increasing the ratio.