ANY steam table is going to be corrupted by bad feed water.
&&&&&&
The FIRST ocean going steam engines -- pretty much through the 19th Century -- used an open cycle -- getting their feed water DIRECTLY from the sea.
They were built in such a way that their boilers would be serviced -- de-scaled -- at virtually every port. (The original transits were between America and Europe.)
This stupidity went on and on. It took years after the Carnot ( pronounced: kar-know ) theoretical (reversable) heat engine cycle discovery in the mid 19th Century for the designers realized that a closed cycle (totally recirculating (the water and steam) engine) was THE way to go.
**********
Which brings us to modern steam 'tables.'
[ BTW, to an engineer a "steam table" is a graph or spread sheet array showing the various heat dynamics of steam vs water vs vapor. They were originally developed by Scotch Wiskey distillers -- to get their 'pots' correctly tuned. ]
ANY steam table that has an open cycle needs make-up water.
If the energy comes from resistive coils -- then the make-up water HAS to be extremely pure -- or the device will fail.
Merely softening the water ( salt, ion-exchange beads ) will prove pretty much useless.
The feed water needs reverse osmosis to get ALL of the minerals out of the stream.
This will prove true -- even if the local area has a reputation for 'soft, pure, water.'
As far as the manufacturer is concerned -- this tick assures plenty of after-market service calls and replacement parts. No need to inform the buyer/ user.
