Tank Selection

Well I'd rather have the 125 space but it sounds like you may want to plan out all that you want to do with it. I'd rather go bigger but I would also rather have a smaller tank set up the way I wanted instead of a larger where I find out i can't afford to keep it going or do it correctly.

 

Money being an option you could buy better things for the 40 as the 125 would probably require multipe items (powerheads, lights, etc) that you could get away with just 1 on a 40b. That being said. Most people get a feeling to upgrade from a smaller tank to a larger one So there is that to consider as well.

 

Buy quality used items. I know many go crazy on lighting but I have amazing growth on my cheap ebay LEDS. With a move around the corner, breaking down a 120 will be a chore in its own. I will likely be moving a year from this summer (Summer of 17) to a new house with an unfinished basement. I have a 225 and would like to put a 8 ft extra wide in the basement. still trying to figure out how to setup a 300+ gallon and move everything from the 225 over. At that point my tank will be ever more overloaded of corals.

 

Yeah knowing that you are going to move fairly soon I would go with the 40 breeder. Much easier to pack up a smaller tank like that but still have plenty of room to have fun with until that move happens. I also agree on what others said... equipment for it will be fairly cheap compared to equipment needed for a 125.