DirectX: How to draw smooth 2D water (particle bas

Question

I recently got a water simulation using particles (1000-1500) working (using the stokes equation), but my problem is that I use a IDXSprite which just draws the particles using blue texture quads (7x7), that doesnt look very smooth.

Is there any way or known technique for drawing such systems so the surface will look smooth (and the water shouldnt have the edges from the textures in it)