Honestly, I wouldn't pay that, unless you don't like messing with DIY. IF you choose to pick up something like that, yes, you can integrate that into your existing system. Either get a seperate return pump for it, or tap off of the existing return pump if it has enough power to handle both tanks.
I've been scouring the LFS
's and craigslist myself to build a frag/prop tank, but it'll have it's own sump since I don't have one for my DT. I've picked up some great deals on used equipment like a 140w Taotronics LED
, a 25g main tank, 20g long tank for the sump, heater & heater controller, just picked up a Mag 12 return pump today, and I've got just a little bit more into it than what they want for just that tank...... The frag racks can be built for a couple $$ out of pvc
& eggcrate. The only thing I have left to do is build a stand, pick up a skimmer, drill the tank, and do the plumbing. For the whole system
, I'll probably be about $350-$400 in.