37 Construction, maintenance and repair of artificial ponds and artificial pond installations, in particular bathing pools and their construction parts, including non-woven materials for the bottom, fabric strips, empty or full pond bags for use in ponds, filtering strips and filter cartridges, containers including containers for aspiration of pond surfaces and bottom sediments and grilles for aspiration containers for retaining leaves, filtering containers for fine filters, biological filters, cartridges of filter fabrics, in particular geological textiles, pumps, air pumps, frames, pipe conduits and water supply devices