I just put a power head in my tank and my Pin Cushion is moving out of the flow and he is letting off smoke!!! What the deal what is it? Are my fish going to be OK?
You might want to read up on drip acclimation and testing the SG of the water it was in to make sure it is matched to your display SG before new stock is introduced next time. Inverts especially are prone to osmotic shock.
LF, have you checked your area for other fish stores? Some of the advice they have given you has been either not clearly given, or is questionable to begin with.