Buying the Octopus - does it need to be same model/similar?

[Tiago Machado]

I was looking for Apeks XTX 50 and the octo XTX 40, which is basically the same except the feature o adjust the air.

Question is, is it advisable to pair XTX 50 with the AT20 instead?

That would save me a lot of money so I wonder if there any particular reason I shouldn't do it.

 

[runsongas]

not advisable if you dive cold water often as the at20 does not have the cold water heatsink, atx40 is better choice there. if you don't plan to dive much below 10C, at20 is fine. can also look at atx40/ds4 to save money over xtx50/dst.

 

[CycleCat]

But yes, you can put any octo with the regulator.

I have an XTX100 1st and 2nd with an Aqualung octo.

 

[Aviyes]

In addition to above comments, it is recommended to at least pair same brands for ease in servicing.

 

[Jim Lapenta]

All of my reg sets use the same 2nd stage for an octo as the primary. Why use a reg with less performance in a situation where you have stress already present?

 

[tmassey]

I would go even farther than @Jim Lapenta. If you are doing primary donate (giving the out of air diver the regulator you are already using), why would you want to breathe on an inferior regulator in that situation? And if you are donating your secondary back up regulator to the out of air diver, what kind of a jerk buys some piece of crap to give to someone in an emergency situation?

Spend the extra few dollars and make sure that both of your second stages are quality pieces of equipment. Don’t be a jerk.

 

[formernuke]

I would go even farther than @Jim Lapenta. If you are doing primary donate (giving the out of air diver the regulator you are already using), why would you want to breathe on an inferior regulator in that situation? And if you are donating your secondary back up regulator to the out of air diver, what kind of a jerk buys some piece of crap to give to someone in an emergency situation?

Spend the extra few dollars and make sure that both of your second stages are quality pieces of equipment. Don’t be a jerk.

Add in even if you are not primary donate there is a chance you will wind up with the octo.

 

[The Chairman]

Both seconds should be identical. The bitterness of poor quality will long outlive any sweetness derived from spending less.

 

[Bigbella]

The only conceivable issue with mix and match would be regulators with differing IP requirements, say, a primary at 8.5 bar; and a safe second with an 11.5.

One or the other will always suck, in terms of breathing, since either one will be in tune and at variance with the other . . .

 

[Centrals]

I was looking for Apeks XTX 50 and the octo XTX 40, which is basically the same except the feature o adjust the air.

Question is, is it advisable to pair XTX 50 with the AT20 instead?

That would save me a lot of money so I wonder if there any particular reason I shouldn't do it.

From your other post on reg you have mentioned that you will NOT be doing any cold water diving.
Cold water is below 10C.
AT20 is NOT for cold water diving, it lacks the heat exchanger on the inlet. 40,50,100 and 200 series all have that feature.
The core of the 2nd stage of all these models from 20 to 200 is more or less the same, the major differences is the fine turning in that adjusting knob(only on 50,100 and 200).
To answer your question(no cold water diving): YES
Actually you can use it as your main 2nd stage as well.
I have the ancient T20 as my octo(rec or tec) for well over 20 yrs.

Look up the service manual of eg 20 and 50 and compare the part number and you should notice the similarity especially on the moving parts.
Learn how to service Apeks regs would save you even more money in the future as long as you can get the service kits(1 set each for 1st and 2nd). Dead easy for Apeks.