New Tank Questions

[BadaBing]

I have all my own gear except tanks, which I've always rented. To help with my own safety, I just purchased a pony setup. I have a standard regulator with the small pressure gauge screwed into the first stage. I also picked up a 30cf Catalina tank with a Genesis valve. The tank came in a plastic bag and the valve came in a separate package. Here are my questions:

Do I go ahead and screw in the valve, or leave it off because someone needs to do a visual inspection?

If I do install the valve, is there some specification for torque?

I almost exclusively dive Nitrox (and I always dive the same mix for each dive on a given day -- eliminates one opportunity for me to screw up by not resetting mix on my computer between dives). Should I also have the same Nitrox mix in the pony tank?

One more question, this one will probably get me yelled at. 30cf is a decent amount of air. Given the best I usually find on rentals is AL100's, I'll now be able to carry 30% more gas. I'm a big-time air-sucker and blow through an AL100 well before I run out of bottom time (I'm working on that). Is it a mortal sin to use the pony to extend my bottom time?

Thanks!

 

[Captain12Pk]

If the tank has not been VIP'd, I'd just leave the valve off, because someone in the shop is gonna want to take it right back off ayway. Yeas there is a specific torque value for valves, but I don'r remember what it is. Most of us just use "hand tight".
I would use the same gas in my pony that I had on my back.
Personally (knowing what I know now), I would have suggested a 40cf, but that's just me. Plan your dive based on your back gas and you should always have a 30cf "safety margin". Personally I wouldn't suggest using your pony to extend your time. Work on your breathing.

 

[Tigerman]

IMO using the pony to extend bottomn time defies the point of having it in the first place. Thats jut my opinion though..

 

[mksmith713]

I'm not going to tell you what or what not to do with your pony but I would never use a pony to extend my bottom time.

Scenario: You use your pony to get 20 more minutes bottom time on a first dive of a two tank trip.
During your second dive something goes wrong with your first stage or tank valve and you lose your entire tank volume in a matter of seconds.
What do you do now?
You still have at least one safety stop to make.
This is why I carry a pony.

 

[joe8mofo]

I would fill it with 40% and switch to it for use during my ascent and safety stop to increase the rate of off-gassing nitrogen. I mentioned 40% assuming that his EAN cert limits the OP to 40%, otherwise 50% would be better.

 

[Trompie]

BadaBing, I dive regularly with a 100 and a 40 that I hang. I ask myself, what is the difference between planning a dive with a 100 my back and 40 on my side versus only a set of doubles on my back?

I realize that I would probably get a fair amount of critique, never the less, when diving a familiar spot; I don't see the issue here. Would I do it on my first deep wreck dive? Definitely not. I guess what I am trying to say is that common sense should prevail.

Perhaps I am missing something here as a result of my limited experience? I just don't see why I shouldn’t plan to use my 40 on a regular recreational type dive. In addition, it is also a good way for me to practice using it and always knowing that my equipment is working as I expect it to work.

 

[BadaBing]

Thanks all for the responses. Sounds like I should just take the tank and valve in and have them do the inspect/fill before I do my next dive.

I figured the extending bottom time question was loaded. I consider myself a conservative diver -- Deepest I've been is 127 feet (air), and I've never put my computer in deco mode. I probably just need to get it straight in my head that all that money I just laid out for my pony setup is an insurance policy, and that I won't derive any direct benefit other than peace of mind. I'm leaning toward trying to synch the pony with whatever mix I'm diving. If I have a primary regulator malfunction, then I'm done for the day anyway. If for some reason I need to go to the pony but my gear is working, then I haven't screwed up my computer/tables. I spearfish, and stuff happens.

 

[rstofer]

I'm leaning toward trying to synch the pony with whatever mix I'm diving.

Good luck with that! I can't even keep the proper mix in the main tanks. I keep my tanks filled (primarily 36%) and, from time to time, have to dump the tanks and get something else, usually just air.

The pony bottle is your absolute last chance to get to the surface alive. Assuming recreational limits and no deco obligation, I would keep it filled with air. There's no point in having 40% at 127 feet.

Opinions vary...

Richard

 

[oldsalt]

I use a pony to extend my bottom time with the following conditions.(1) It is the last dive of the day and I won't need the pony again, and (2) I have completed any deco obligation, including my safety stop and I am able to pop up to the surface. I don'e see any problem paddling around in 15 ft of water checking out the sea life. Some of my best experiences, e.g. encountering mating squid, occured after the "real dive" was over and I was just hanging out in the shallows. - oldsalt

 

[ianr33]

Is it a mortal sin to use the pony to extend my bottom time?

Thanks!

What happens when your main tank is almost empty,you switch to the pony at 130 feet , and find it does not work for whatever reason?

You NEVER want to be in the position of your life depending on a single piece of gear working as expected.