Next use a half cup of regular baking soda dissolved in a bucket of water. Fill the tank again and then drain it. Then fill and drain it one more time. At this point your tank should be pristine. Make sure you drain the system if your RV is to be left in cold weather.
Burst pipes can cause a great deal of damage.
Water leaks are the bane of RVers. If a connection gets loose, water gets in. A good seal is essential to avoide dry rot. Check your roofs for gaps. Do not use a silicone sealer anywhere except around windows as it can become brittle.