Water purification and filtration apparatus; Swimming pool chlorinating apparatus; Heaters for swimming pools; Swimming pool water cleaning and filtering units; Filters, heaters and pumps sold in combination for use in swimming pools; Water filtering apparatus; Water filtration and purification units and replacement cartridges and filters therefor; Membrane filters for water filtering apparatus; Accessories for fireplaces, namely, ventilation hoods for fireplaces for use in ventilation and de...