Plumbing confusion

[freaky1]

I have purchased my 1074 outlet. I am wondering about the following.

The outlet from the 1074 is 32mm. The outlet hose fittings (1075/2) state a 40mm hose ?

I haven't putchased the 1075/2 yet, but is there some type of reducer to connect the 40mm hose to the 32mm outlet on the 1074 ?

Is this size hose required to acheive the full flowrate of 900l/h ?

 

[rvitko]

The oversize hose dampens noise. I don't recall if the coupler is included with the hose or the overflow box but there is one.