See ref.
Meso-mineral waters: between 200 and 1,000 mg/ L
https://books.google.com.ar/books?id=-d1YDwAAQBAJ&pg=PT99&lp...
According to the chemical composition, the mineral waters may be classified as (according to Marotta and Sica). 1. Oligomineral: less than 0.20 %0 residue at 180°C. 2. Mesomineral: between 0.20 °/00 and 1.00 %0 residue at 180°C.
http://pubs.geothermal-library.org/lib/grc/1005273.pdf
On the right bank of the Tâmega river, in and around the town centre of Chaves, natural mineral water springs occur with a unique composition; they are hyper-thermal, at 73 ºC, meso-mineralized and gaso-carbon and contain bicarbonate of soda.
www.cultourplus.info/wp-content/uploads/2018/05/Internation...

When a water contains less than oS"i-6 of solid residue in a litre and is thermal, it is termed hypomineral or indifferent; when the residue is between o.6 and Ss"^-, it is mesomineral or moderately mineral; and when it exceeds 3^"^-, it is hypermineral or very mineral or very saline. A simple table or aerated water is usually cold; it contains less than os™-3, of solid residue, and is styled protomineral or feebly mineral.

As regards the total solid residue, there are only two spas which are hypermineral or very mineral, namely, San Paulo and Vidago ; whereas all the others,with the exception of the indifferent or the simple thermal waters, are mesomineral or moderately mineral.
https://ia800304.us.archive.org/29/items/climateofportuga00d...