I am hoping someone can give me some advice please. I just bought 1st RV, 2009 Keystone Montana as cottage on our property last year. All was good but few weeks ago, noticed Hot water was black and stunk. Read some blogs here and cleaned Hot water tank with vinegar and replaced Magnesium anode rod. Came back next week and water was black again, but did not smell? Any ideas what next? Have Suburban water heater and all water is soft from our home. Thank you for advice.