I had a 55 and 72 gal fish only tanks and only topped off my water, I never did water changes like others. I have a new 90gal reef corals and fish that Im moving today at 8am. All I hear about is water changes every week or two. If I mix up water how long will it last in a 30gal trash can?? Do you need to do water changes if everything is doing well and water tests are ok?


