The present invention relates to a composition comprising one or more quaternary ester ammonium compounds (a), one or more amidoamine compounds (b), wherein the weight ratio between the one or more quaternary ester ammonium compounds (a) and the one or more amidoamine compounds (b) is within a range of 1:5 to 5:1, and one or more fatty alcohols (c). The present invention also relates to a composition that is solid at room temperature, to a hair conditioner composition and to a method to prepare the hair conditioner composition by dispersing the solid composition in water at moderate temperatures. The present invention relates to a composition comprising one or more quaternary ester ammonium compounds (a), one or more amidoamine compounds (b), wherein the weight ratio between the one or more quaternary ester ammonium compounds (a) and the one or more amidoamine compounds (b) is within a range of 1:5 to 5:1, and one or more fatty alcohols (c). The present invention also relates to a composition that is solid at room temperature, to a hair conditioner composition and to a method to prepare the hair conditioner composition by dispersing the solid composition in water at moderate temperatures. The present invention provides subsea seawater filtration and treatment system, comprising a filtration assembly (1,3) for filtering out particles and detritus from the seawater a first pump (5) comprising an inlet in fluid communication with the filtration assembly (1,3) and an outlet a sulphate removal unit (6) comprising an inlet in fluid communication with the outlet of the first pump (5), a first fraction outlet for sulphate depleted seawater and a second fraction outlet for sulphate enriched seawater at least one second pump (7) comprising an inlet in fluid communication with the first fraction outlet, and an outlet for the sulphate depleted seawater wherein the second fraction outlet is in fluid communication with the filtration assembly (1,3), such that the sulphate enriche
