so i have quite a few nems right now and i want to move some of them into their own tank. i want the tank to be below my current frag tank which is in a back room of the house. so heres a pic.

20131231 182648 zpscc9a3f0f - advice needed for frag tank/ nem tank addtions

so on top is a 40 long, and below is a 40 breeder. i have a eshoppes HOB skimmer for 75 gal, t5 lights for the top tank and an LED fixture for the bottom tank, i have several heaters laying around, extra power heads the whole works.

so my question is, do you think i should tie the two together, and make the 40 breeder a sump and nem tank? or no? here are the two senarios....

1) tie them together. i have a skimmer that can handle that much water, i have a heater that can handle it, i have glass for baffles, and this would allow me to add an ATO to the system. so things to buy....
-overflow box (maybe $25 used)
-return pump ( maybe $75 used)
-ATO ( ~$100)
-silicone ($10)
TOTAL= ~$210

2)keep them separate. i would have to keep topping off via gravity with air line tubing almost daily (PITA and now i would have 2 tank to top off manually). it would prevent contamination of pests if i ever got one. i would have to buy another skimmer. things to buy.
-Skimmer ($135)

this should be done withing the next couple days, i have the water mixing up now. so whats your opinion?