If I were you, I would take time to save up some more and get a better tripod. To be honest, with the D800, a tripod will be collecting dust at home most of the time. You will find that cranking up the ISO work really well in many situations (I don't mean all situation).
For the tripod, you may want to visit camera stores that have lot of tripods on display. If you go play with them, you will found most tripods on display developed some defects because of all the abusive handling from customers. You will know how to choose after visited a few store!
I can only suggest Gitzo tripod and Arca-Swiss Z1 ballhead or Manfrotto 405 geared head. I use them and they are reliable to my experience.