bio load

Ok I’m currently running a fx6 on a 5ft 125g tank , perfectly balanced never an unexpected spike in quality the whole system supports any bio load I have in there , leading to the question of if I moved everything out of that tank into a 250g indoor pond would the bio load still be supported...

Iv been half heartedly trying to rehome my silver dollars , no rush just changed my mind on them and slowly looking to move them on . Iv been offered a swap of a snowball pleco for the 5 , money comparison doesn’t really interest me but the bio load does main reason for getting rid of them is...