Max flow through 1"?

[Dickeybrazil]

I have a 90g, Herbie plumbed (holes in bottom if that matters). I have the new COR-20 pump on order, so pump should be sufficient to get 10x flow (900 gph). What is the maximum flow that will gravity drain through my 1" normal drain?

 

[mfinn]

Assuming the siphon is perfect and air doesn't interfere, I've read up to 900 gph.
But you can never count on anything working perfectly

But I think the actual number is closer to 600gph.