A cleaning arrangement configured to be used in a liquid treatment system, where said liquid treatment system comprises at least one ultra-violet light treatment lamp arranged within an elongated protective UV-transparent sleeve provided along a central longitudinal axis A, said sleeve having an outer surface and an essentially circular cross-sectional shape and a reactor configured to receive said sleeve, whereby a liquid treatment chamber for receiving liquid to be treated, is provided between an inner surface of the reactor and the outer surface of the sleeve, characterised in that said cleaning arrangement comprises: - at least two coil springs, which are provided in the cleaning arrangement such that they will be wrapped around at least a part of a circumference of a sleeve of a liquid treatment system when the cleaning arrangement is provided in a liquid treatment system and such that a spring force of the at least two coil springs will press the coil springs towards the sleeve, wherein said cleaning arrangement is configured to be moved along the sleeve and the coil springs will clean the outer surface of the sleeve, wherein said at least two coil springs are mounted in a holder of the cleaning arrangement such that the coil springs together wrap over essentially the whole circumference of a sleeve of a liquid treatment system when the cleaning arrangement is provided in a liquid treatment system, wherein said holder of the cleaning arrangement comprises a first ring shaped coil spring attachment part and a second ring shaped coil spring attachment part which are connected to each other such that they are provided at a distance from each other, wherein the first and second coil spring attachment parts (31a, 31b) are configured to encircle a sleeve of a liquid treatment system when the cleaning arrangement is provided in a liquid treatment system and configured to be movable along the sleeve and wherein a first end of each coil spring of the cleaning arrangement is attached to the first coil spring attachment part and a second end of each coil spring is attached to the second coil spring attachment part such that each coil spring will wrap around a part of the circumference of the sleeve when the cleaning arrangement is provided in a liquid treatment system, wherein the coil springs are not connected the shortest way between the first and second coil spring attachment parts (31a, 31b) but instead mounted diagonally in a rotational pattern in the holder. said liquid treatment system comprises at least one ultra-violet light treatment lamp arranged within an elongated protective UV-transparent sleeve provided along a central longitudinal axis A, said sleeve having an outer surface and an essentially circular cross-sectional shape and a reactor configured to receive said sleeve, whereby a liquid treatment chamber for receiving liquid to be treated, is provided between an inner surface of the reactor and the outer surface of the sleeve, characterised in that said cleaning arrangement comprises: - at least two coil springs, which are provided in the cleaning arrangement such that they will be wrapped around at least a part of a circumference of a sleeve of a liquid treatment system when the cleaning arrangement is provided in a liquid treatment system and such that a spring force of the at least two coil springs will press the coil springs towards the sleeve, wherein said cleaning arrangement is configured to be moved along the sleeve and the coil springs will clean the outer surface of the sleeve, - at least two coil springs, which are provided in the cleaning arrangement such that they will be wrapped around at least a part of a circumference of a sleeve of a liquid treatment system when the cleaning arrangement is provided in a liquid treatment system and such that a spring force of the at least two coil springs will press the coil springs towards the sleeve, wherein said cleaning arrangement is configured to be moved along the sleeve and the coil springs will clean the outer surface of the sleeve, wherein said at least two coil springs are mounted in a holder of the cleaning arrangement such that the coil springs together wrap over essentially the whole circumference of a sleeve of a liquid treatment system when the cleaning arrangement is provided in a liquid treatment system, wherein said holder of the cleaning arrangement comprises a first ring shaped coil spring attachment part and a second ring shaped coil spring attachment part which are connected to each other such that they are provided at a distance from each other, wherein the first and second coil spring attachment parts (31a, 31b) are configured to encircle a sleeve of a liquid treatment system when the cleaning arrangement is provided in a liquid treatment system and configured to be movable along the sleeve and wherein a first end of each coil spring of the cleaning arrangement is attached to the first coil spring attachment part and a second end of each coil spring is attached to the second coil spring attachment part such that each coil spring will wrap around a part of the circumference of the sleeve when the cleaning arrangement is provided in a liquid treatment system, wherein the coil springs are not connected the shortest way between the first and second coil spring attachment parts (31a, 31b) but instead mounted diagonally in a rotational pattern in the holder.