Regarding descaling chemicals - You have got me there - I can only remember a product called Saf -Acid. As I recall it was a powder and came in cardboard drums But as it was made by Drew Chemical Corp. then I guess it must have been from my days with Fyffes rather than Brocks.
Re-Maturata I remember she had glass air heater tubes in her Scotch Boilers.
These were made by Pilkingtons as a replacement for the corrosion prone mild steel variety. Despite extensive testing by Pilkington Maturata seemed very capable of shattering them. I beleve they were on trial on Maturata. - Did the experiment continue and were they used on other ships? At least tube replacement was quite straightforward.