Yes, much better to find the reason for the green water and solve it rather than put a band-aid on it. Most likely phosphates are too high in the water you are using for waterchanges. I have to use RO water due to 6-8ppm in my tap water. Maybe you need to pre-condition your incoming water to get rid of the offending nutrient. It's most commonly phosphate so pre-treatment with phosphate resins, RO or ion exchange would solve the problem. Also check the food you are using is not rich in phosphate. Are you using water conditioners or activated carbon? Some of these can be a source of phosphates, - especially pH stabilising ones. Some brands of activated carbon can release phosphates...