Help Liquid-to-Liquid Collision

[josemendez]

Does this mean that something like the plan I am working on is impossible?

if I understood it correctly, it is completely possible to do what you want. You just need to use diffusion instead of relying on collisions between particles (which won't happen for fluids).

Also, for example, is it feasible to put a solid in a liquid, and when it comes in contact with the liquid, the liquid will change color and the solid will gradually decrease in size?

This is exactly what the FluidMaze sample scene does (minus the solid gradually decreasing in size, which can be done just by scaling it). Check its components to see how it's done.