I'm just wondering, whenever my LFS or any pet store asks me about water changes when I get my water tested, they freak out when I say I do 75% water changes weekly. I always do 75% weekly water changes because I thought it was good for my fish and they all do well with large water changes. Why do fish and pet store workers tell people to do 25% water changes monthly? At least that's what I'm told. It's confusing because I'm always getting different information from different stores. I know from personal experience that 75% weekly water changes keep my fish healthy and my parameters good. I'm going to continue with 75% water changes but I'm just curious why pet and fish store workers never understand that large water changes are good for the fish? Am I correct in doing these large water changes? Thanks in advance.