Display reef set-up with old innards

[sawdavis]

I have a 75 gallon tank that is about two to three years old with fish, coral and live rock. Unfortunately, the display tank has a lot of scratches and I would like to replace it but keep everything else. Do I need to recycle it as though it is new? What is the best way to proceed?

 

[New&no clue]

I upgraded my tank from 55 to 75, i kept everything from the 55 and moved it to the 75, except for the sand. I didn't experience a new cycle, some cloudy water but that was about it.

 

[southerntnreefer]

I upgraded my 125 to a 220 and kept same sump and rock, etc and just replaced the sand with new live sand and called it a day. Nothing really. Had good readings within a few days. No spikes from what my testing showed. Been good since.

 

[sawdavis]

Why not use the old sand?