120 students from Cita Hati junior high school Surabaya visited ECOTON to observe water quality in Surabaya river. They use the water insect / BIOTILIC method to determine the quality of water in the Surabaya river. The BIOTILIC method is known as a simple method of measuring water quality because it has 4M properties (Cheap, Easy, Bulk, Benefit).
For 1 hour they watched the insects they got from the Surabaya River. By using a guidebook on water bugs they differentiate the types of insects that are tolerant and intolerant of pollution in Surabaya river. Water bugs are an indicator determining the quality of water in rivers.