I read somewhere on the web and said not to use carbon filter with discus. I have my discus in a planted tanks so that's why i am using carbon filter in my my fluval 405. Is there any negative impact on the discus for using carbon? Thanks.
I don't know where the idea of carbon harming discus came from. This is the second time this week I heard about it. Tuesday was the 1st time I ever heard anything about it. I've kept discus with carbon, raised discus fry with carbon, and done both without carbon. The difference is you don't have to replace the carbon 3+ times a month. A properly filtered and water changed aquarium does not need carbon.
Short answer IME carbon will not harm discus.