Apeks Octo Recommendations?

[Centrals]

When needed, you like the backup to be as good as your primary, it is when the **** hits the fan you like to have good equipment.

I have been using T20, TX40, ATX40 and TX50 on both rec and tec for many yrs(>20yrs) and I serviced them myself as well. All of them are identical mechanically, same barrel, the only difference is the adjusting screw on 50, the smaller size of ATX40 and the lack of heat-exchanger on T20.
I had a look at the inner of XTX 2nd stage few yrs ago and came out with the same conclusion. So unless Apeks had made some dramatic changes on the 2nd stage over last few yrs, both 40 and 50 should breath the same.

 

[gcarter]

I think you mean the adjustment screw knob, not the Venturi. Both models have the Venturi switch.

Yes.