fish sauce production

Which soda Na2CO3 is used as fish sauce?
According to the regulations of the Ministry of Health, Na2CO3 soda is allowed to be used in food but must be used for food, and Na2CO3 used in industry is very toxic to health.
Producing fish sauce with solar energy
Shorten fish sauce production time to 6 months, instead of 10-12 months as before. Obtain more than 30% of fish sauce with traditional production. All these benefits are due to