The invention relates to a method and a product for covering liquid surfaces with the purpose of reducing the evaporation from the liquid or stabilizing the temperature of the liquid. The invention is particularly useful for covering the liquid surface in manure tanks and containers where the liquid evaporation constitutes an ever increasing environmental and obnoxious smell problem. The product consists of floating elements which may be spread over the liquid surface and cover it effectively, as the basic shape of the elements are triangles, quadrangles or hexagons of the same angle, which are mutually shape-equivalent and may be combined without gap airs and optionally with mutual, symmetrical overlap ( 4 , 5 ) between the individual modules.
