Alternative Activities to Water and Soap Play

My daughter is obsessed with playing with water and fish washing soap.  She whisks the soap until it forms thick peaks and adds more water and soap depending on which one she needs.  I want to reduce that obsession and I would like to know activities that can give her same function.  She is happy when she plays with it and it's calming or relaxing for her. I don't know if it's a sensory overload or underload thing, but I really need to reduce her attachment to it.