It is worth knowing that once the chemical balance of a domestic swimming pool is stabilised many of the chemicals that are sold in pool shops are no different from those readily available in supermarkets.
For example one brand of ‘Alkalinity Increaser’ shows it’s active constituent as being 100% Sodium Hydrogen Carbonate. This is just another name for sodium bicarbonate or baking soda so it’s worth comparing the price in the pool shop with the price in the supermarket.
180 grams of Sodium Bicarbonate in 10000 litres of pool water will raise the total alkalinity of pool water by 10ppm.