If you don't have a factory installed black flush port ( garden hose adaptor that sprays the inside of the black tank ) then one of the tank drain adapters with a hose port is a good choice
Drain black tank first, followed by grey. This will flush black waste out of the drain hose.
Before you drain your fresh water tank, or disconnect from city, and after you have drained and flushed out the best you can add a gallon or 2 of fresh water back to the toilet, by holding the flush handle open for a minute to two.
Then throw in the chemicals to help keep odor down.
If you do put Ice in the tank, it will melt and become the water mentioned above.
Jim & Kim from Colorado
2014 Eagle 30.5 RLS
2015 Dodge 3500HD SRW 6.7L
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