A few weeks ago I found a good deal on a used Eheim 2213 with all media etc. After attempting to set it up I noticed I had 3 female shut off valves and 1 male. The seller had 3 2213s one buyer I asked said his was fine and to date, the other person who must have 3 male 1 female has not been tracked down. The sale ad/purchase was through a local fish forum and we are all members so there is a chance it will be sorted out. My question is because my LFS wants $40cdn for a pair of valves. Who is using one with just straight tubing? Is there a difference? Big hassle during maintenance? I bought the filter for $40cdn and they can be purchased new for $110-$130 so I don't want to sink another $40 in to this used filter.