Uh I found a 20 Long in my shed.

I like the way its set up but my 15 is a really awkward size. 20x18x10. I think a 20 long would be better for the livestock I have/plan on having

 

Would I just have to spring for fully cured live rock avoid the cycle?

 

If you mean you want to add more rock why not just pick up some dry base rock. Its half the price and won't give you a cycle.

 

I say got for it. It will increase your overall volume with the tank plus sump, give you an option for a fuge.

I cut and paste the following from another thread where I posted this....

The fuge will increase your water volume, serve as a place for your macro and mangroves, home for production of copepods, decrease fluctuations in parameters because of increased volume, good place to hide heaters, or in my case i left the heater in my tank and put a another one in the fuge so if ever one fails, i got back up. The fuge also serves as a quarantine in ways. You can NOT dose copper meds or wtvr but like if a fish is gettin beat up or needs to be seperated. I have a damsel living in mine rite now as well as a snail i discovered trying to eat my ceriths. The water levels in your tank dont go down, the top off goes into the fuge, which is easier to do than having to lift a 5 gallon bucket to top off evaporated water because it at floor level.

 

I'm pretty sure i'm gonna do it. Gonna have to wait untill after christmas though.