TWO park wardens have been rewarded for designing a method of recycling water. Hui Fuk-pau and Chun Mo-man of Tuen Mun Town Park were inspired by watching how water was re-used in fish talks. They devised a scheme which allows water used in the park's ornamental lake to be recycled for irrigation. The two amenity assistants were presented with $10,000 and certificates yesterday as winners of the Regional Services Department Suggestions Scheme Award. ''The theory behind this system is very simple,'' Mr Hui said. ''We give the water to the fish first and after the fish have used it, we give it to the plants. The fresh water which used to be used for irrigation can now be used to refill the lake.'' Deputy Director (Administration) Albert Lai Kwok-ying said the department considered more expensive solutions, but the new method would be cheaper, costing only $50,000.