[en] It is shown that for certain graded locally convex topologies on a filtrated *-algebra the closure of the cone of all finite sums of squares is precisely the cone of all infinite (convergent) sums of squares, similar to the case of the test function algebra. The result applies to tensor algebras and symmetrized tensor algebras over involutive nuclear Frechet spaces and to some finitely generated *-algebras such as polynomial algebras, the Weyl algebra and enveloping algebras