CO2 Regulator: Single vs Dual stage?

[lozt]

I'm looking to finally getting a real CO2 setup, but i'm having a hard time finding an good and affordable regulator.

I see a lot of people suggest Azoo, but it's single stage.
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=9895

From what I understand, for a single stage regulator it can have an "end-of-the-tank dump" which empties the last portions of the cylinder into your fish tank all at once which could kill your fish.
Does this happen every time your tank is almost empty or it is more or less just a possibility?

 

[HybridHerp]

I think it really depends on the quality of the regulator, but I went with a dual stage just for peace of mind. I'm also away from my tanks for weeks at a time and leave them with my parents care, and they aren't going to be messing with the co2 stuff so I'd rather play it safe than sorry.