Bought a display model dishwasher from Home Depot. I don't think it was ever a working unit or hooked up before I bought it. This thing has never worked correctly. No matter what soap I use it never cleans the dishes. It also never rinses them very well because there is white stuff all over them when the dishwasher turns off. I don't think we have hard water here so I'm guessing it's the soap that I'm seeing. Any idea on where to start troubleshooting this?