The Corsair HydroCool WC'ing system recommended flushing is with 50% Distilled White Vinegar mixed with 50% Distilled Water.
The HydroCool uses micro-channels in the cold-block. They are very narrow and long. So, purging out the Storm shouldn't be a problem at all.
The only item to really consider to purge as a new product should only be the radiator. There "could be" left over braze filler or flux from the manufacturing process. Other than than, why subject the other parts in the kit to a cleaning?
Do not use lemon juice concentrate to flush a WC'ing setup. Lemon juice is good for cleaning the copper on the OUTSIDE of the cold-block and base. Lemon juice is NOT good to clean aluminum.
Lemon juice: is a weak solution of citric acid and is a mild bleach, deodorant and cleaning agent.
Distilled White Vinegar: is a dilute solution of acetic acid. It is used as a bleach, disinfectant, deodorant, and anti-mould cleaner.
Do not use salts of any kind in a WC'ing setup. The are very corrosive to the metals.
Do not use ammonia either. It will react badly with copper.