I have a 120G tank coming next Tuesday: 48"x24"x24." It is made of 3/4" acrylic with an external coast-to-coast overflow and a Eurobrace and cross-brace. There are two return holes drilled at the upper right and upper left part of the tank (so the overflow is not quite coast-to-coast). These accommodate a standard 3/4" bulkhead. The external overflow has three 1" bulkheads in the bottom of the overflow for a BeanAnimal drain system. I am actually replacing an almost identical tank, so I will need to replumb the tank. In doing so, I am moving the sump from underneath the tank to the fish room on the other side of the wall behind the tank. The move will make the sump more easily accessable and will make it easier to plumb in two more ~25G (200gph) tanks for my cuttlefish rearing system. The first time I plumbed this tank, I used all 1.5" Schedule 80 with a gate value on the siphon drain and a ball valve on the open channel drain. It was very expensive and complete overkill. I barely had the gate value open on the siphon drain and barely any water went down the open channel drain. Since I want to go behind the wall, my plan is to try to plumb this much simpler and cheaper this time around. I am going to use 1" ultra flex PVC from Marine Depot. The drain (3x1") and return (2x3/4") bulkheads are all threaded so things are "undoable," so I need to go from the threaded bulkheads down into the stand then out the back wall then across the fish room to the sump. I want to reduce the number of connections and things, since my experience is that each one is an opportunity for leakage and salt creep. OK, now the two main questions: (1) In the first setup, I used 1" clear tubing for the returns but then used a special barb elbow that went from 1" bard to 3/4" FNPT that then went onto the threaded 3/4" bulkhead. The idea was the the 1" tubing from the return pump has less friction, so I ran the 1" tubing from the return to a 1" Y and then 1" up to the two return bulkheads with the reducing barb hose elbows. This turned out to be very hard to get the threaded elbow onto the bulkhead. I did it, but it was not trivial. Is there a better way to do this? I wold think this is a common thing to do (ie, run bigger tubing to the bulkhead and then drop down the diameter at the return bulkhead). (2) From the 1" threaded drain bulkheads, I was going to use a Female Adapter Fitting - 1 inch FPT x 1 inch Slip and then PVC glue the ulta-flex tube to the slip and run the line all the way into the fish room. If I ever need to remove this, I can always undo the bulkhead. The values (Gate for the siphon, ball for the open channel) will be in the fish room. This should keep the noise inside tubes down on the living room side. Again, any downsides to this approach? Once I get into the fish room it is a little more complicated. Instead of having all three tanks drain into the sump separately, I was going to have the two smaller 200gph tanks join the open channel line from the 120G tank by going from 1" to 1.5" with reducing Ts. There are two filter socks in the sump that can hold up to 1.5" PVC. This means my 1" open channel drain line will use an adapter to step up to 1.5" ulta spaflex and the two smaller tanks' drains will T into this with the 1" to 1.5" Ts. I think that is all OK since this line should have plenty of capacity.