I always add it to my lye mixture, with silk and clay, but learned to go lightly, maybe 1 tsp ppo. Adding too much gave me CP bars that were too hard to the point of being kinda crumbly, and a kind of unnatural white color. I also always add it right after the cook in HP, find it really helps in keeping it gelatinous enough to be able to glop into the mold without many air bubbles - and still do pretty textured tops.