Pond was dug in April 2018, due to work being done around the new home build it made no sense to seed grass. I seeded grass in October with little germination.

Since the house was a new build I used the topsoil from around the pond around the house. And now I have a pond surrounded by nothing but clay an have had a hard time w/ the grass.

What type of grass is best for growing in heavy clay? Should I bite the bullet and have a load of topsoil hauled in to use around the pond... not really want I want to spend $ on right now... but on the other hand my water is really dirty and I need to get grass established to clear the water.