Some more information to add to your heated disscussion, anyone lifting safety valves yet?
I have seen some engine makers, Deutz for one, that supply "Filter Cartridges" to fit in the water circuit, usually in a bypass line, these are solid blocks of chemical, in a metal case, that dissolve and maintain the coolant saturated, you weigh the cartridge to check if it is depleted or not. The new filters weigh a ton, the empty one is not much heavier than an empty beer can)
Some suppliers, such as Unitor supply the corrossion inhibitor as a powder (Dieselguard NB) or a liquid (Rocor NB Liquid). These are Chemically the same, a Nitrite/ Borate based compound with organic corrosion inhibitors) Usually the liquid is much easier to use, but the powder has to be mixed with water to ensure it dissolves, before being added to the header tank. However, if you buy the liquid, you are paying for packaging and transporting a lot of water, so the powders are usually much more cost effective.
These Chemicals attack Aluminium and Zinc, so if you have these metals in your coolant circuit, you have to use other coolants, I know Unitor make one but I can't remember the name.
In the case of lifeboat engines and emergency generators, on a World Wide Trading vessel or one trading to cold areas, these coolant systems should always be treated with a combined anti freeze and corrossion inhibitor. Don't mix the antifreeze with your usual corossion inhibitor!!
(The should also be fueled with "wax free" winter grade DERV.)
Keep discussing and asking questions, it is the best way to learn.
It is always better to ask a stupid question than to do a stupid thing.