My mixing station is in my basement with the tank in the room above it - I’m wondering if I get the Apex DOS if it makes more sense with the mixing station since I’m going to use it for water changes etc OR does it go up closer to the tank?
It doesn't really matter where you place it - the DOS is more than capable of a very large run (horizontally and vertically). So I guess wherever is most convenient to hook up to your Apex.