Asylumdown's 275 Tank build

[gregzz4]

As for your heaters ....
3-5 watts/g is a good idea. I don't know what your total water volume is or I'd suggest a heater group.
I like having multiple smaller heaters so no single one can cook the tank if it is stuck on and I'm not relying so much on a few to do the job of many.
I have my heaters connected to a controller and they are set 1-2 degrees above my target temp so they always engage.
Also, this way if something goes sideways and they are all permanently on, there's less chance they will thoroughly cook everyone.