I made a mistake once with rice hulls. I thought it would be a good idea to put all the hulls into the strike water first and then add the malts. What happened was all the rice hulls sank right to the bottom under the pressure of the malt and immediately clogged up my stainless false bottom, resulting in a seriously stuck mash. I ended up scooping all the mash out into a separate sparge vessel to finish the mash. Next time I think I'll mix the hulls in with all the grains.