New pump and plumbing

[Humpty]

oops i didnt see the above post before i posted the last one.
So if i am running one pump instead of 2 should i get a bigger one? maybe the jebao dc12000.
What kind of flowrate should I be looking for? At the moment I am running 2 quietone 6000s, but according to the flow chart I am only getting about 750gph out of each. I have a 180g tank and 80g sump.
It looks like a dc12000 plumbed like you said would get more flow rate then 2 quietones the way they are now.
Currently i have a reef octopus 5000sss skimmer.