Can't change colour of material on Prefab

Hello all,

I’m instantiating a prefab and trying to change it’s tint colour, but I’m not having much success :

glow = (GameObject)Instantiate(MyGlowPrefab, Vector3.zero, Quaternion.identity);
glow.name = "My Glow";
glow.renderer.material.color = Color.magenta;

… but the prefab doesn’t change colour. If I trace the material.name, it’s the correct material, and if I disable the renderer for ‘glow’ it doesn’t appear (so I’m referencing the correct renderer).

The shader is a particles/additive shader and all I’m trying to do is use the same glow png, just tinted for different conditions.

Can anyone help me out?

See here.