I have a single that I will be replacing with a double perhaps this weekend as I will probably be altering my canopy to install my 4 vho actinics, reconfiguring the lid/top and staining it darker...sheesh...very relaxing hobby...lol You could borrow it for a while. And yes, the only way to temporarily re-route the extra flow is 1) into your sump and 2) into your skimmer if possible 3) use a gate valve to throttle it back but that puts a little more wear and tear on the pump depending on how much throttle. (As far as I know) Oh...you will need to use or get your own hose as I am re using the original.
HTH