Hi pixel1327,
There is more about the different types of support systems that are generally most suitable for different types of mattresses and some examples of each of them in the foundation post here.
With a mattress that has a polyfoam support core then a wire grid foundation (see post #10 here) or a slatted foundation that has gaps that are about 5" or less would generally be a suitable choice although smaller gaps between slats or smaller spacing in the grid would still be more supportive and preferable.
Phoenix