That’s ridiculous. You need a mg scale and pH strips as equipment (~ 20€, once); tap water, pure vitamin C and sodium bicarbonate as ingredients (~ 6€, lasts f

That’s ridiculous. You need a mg scale and pH strips as equipment (~ 20€, once); tap water, pure vitamin C and sodium bicarbonate as ingredients (~ 6€, lasts for many, many preparations). Aluminium foil to make any glas container light-tight. The chemicals are food grade from your next supermarket or drug store. The "recipe" is used in some studies.