Cleaning and purifying of the water syystem

Ready to go wrote:Temp now regularly above freezing where we are and planning to go away for our first trip, starting this sunday.
Have a 2021 Broadway which was purchased recently.
Drained all of the systems in the autumn but have never filled from scratch.
Looks like I can connect the Whale electronic system to a tap to fill - but presumably the habitation system needs to be switched on for the pump to take on water? CORRECT - THE POWER BUTTON AND AUTOFILL BUTTONS MUST BE ON ON THE EC700 CP....and, does it stop automatically when full CORRECT - WHEN THE TANK SENSOR SHOWS 100%, or might I have an issue with water still coming out over the electrics? THE FRESHWATER TANK HAS A BREATHER WHICH ALLOWS IT TO OVERFLOW EXTERNALLY AWAY FROM ELECTRICS IF FOR SOME REASON THE AUTOFILL DOES NOT SHUT THE SOLENOID VALVE AT THE WHALE INLET SOCKET WHEN THE TANK IS FULL.  

I've got some Puriclean which I plan to make up, and think I need to add that via a jug on the other water inlet.  I understand this dissolves better if the water is at least warm - which I will do. ITS EASIER TO MAKE UP THE SOLUTION IN AN AQUAROLL OR SOMETHING LIKE IT AND PUMP INTO THE FRESHWATER TANK THROUGH THE WHALE INLET SOCKET USING THE EXTERNAL WHALE PUMP WHICH THE VAN SHOULD HAVE COME WITH. IN THIS WAY THE AQUAROLL, PUMP AND WHALE INLET SOCKET SOLENOID VALVE AND PIPES ALL GET TREATED.

Once full I understand I then need to open all taps to get the system to drain - once it has had a chance to soak for 1-12 hours. IF YOU USE PURICLEAN YOU WILL NEED TO REFILL AND DRAIN TO GET RID OF THE CHLORINE SMELL AND TASTE.  TRUMA DON'T RECOMMEND THE USE OF CHLORINE BASED PRODUCTS.  I USE CITRIC ACID WHICH STERILISES, DESCALES AND DOESN'T LEAVE AN UNPLEASANT TASTE OR SMELL.  I GENERALLY DO IT OVER A COUPLE OF WEEKS WHEN THE VAN IS NOT BEING USED SO EVERYTHING HAS A GOOD SOAK.  I PUMP THE SOLUTION INTO THE TOILET CASSETTE AS WELL AS THE HOT WATER TANK AND ENSURE IT ALL ENDS UP IN THE WASTE WATER TANK SO IT GETS A CLEAN/DESCALE AS WELL.

Keen not to do anything stupid tomorrow which causes a big problem!

Any advice/tips would be appreciated.

Thanks!