Water Testing Strips like the AquaChek Test Strips can be used to test for individual chemicals or you can buy something like AquaChek Select 7 Way Test Strips or Yellow 4 Way Chlorine to make multiple tests at the same time.
Most second-language speakers reside in Francophone Africa, in particular Gabon, Algeria, Mauritius, Senegal and Ivory Coast. In 2015, French was estimated to have 77 to 110 million native speakers, and 190 million secondary speakers. Approximately 274 million people are able to speak the language. According to a demographic projection led by the UniversitÃ© Laval and the RÃ©seau DÃ©mographie de l'Agence universitaire de la francophonie, total French speakers will number approximately 500 million people in 2025 and 650 million people by 2050.
There are roughly 6,500 spoken languages in the world today. However, about 2,000 of those languages have fewer than 1,000 speakers. The most popular language in the world is Mandarin Chinese. There are 1,213,000,000 people in the world that speak that language. You might also like our list of the most widely spoken languages in the world.