unidentified polyp coral

mo, there fine lol, i just put them in the tank, they just now opened up, i have another question for you all, i have some yellow polyps and every time i add some purple up or change the water (incuding adding chemicals, i.e essential elements and other buffers) they seem to shrink up, they look pitiful, but the next day theyll be fine, whats the problem?

They are probably just excreting waste or eating.