I purchased the 10 gallon tank with my CSV valve and was planning on installing the tank horizontally until I read in the CSV instructions that if using the 10 Gal tank it MUST be mounted vertically. I have seen some of the pictures in the review section that show some people having it horizontally mounted. Is the note in the instructions mainly due to the extra weight concern or is there another reason that it should be mounted vertically? I was going to provide extra support for the tank if mounting horizontally.