I do have a button gauge on it, only because it makes it easy to check on the surface. But I don't understand why you think it's important to be able to check it underwater. If you plan on being able to share your pony under the water, you should have taken into account the gas consumption rate of you and your buddy on an emergency ascent.
Hello Carrie,
I agree with you, "if you don't have proper gas management once you are underwater it no longer matters if it has a gauge". I never plan on using my pony, and the only time I did use it (due to my foolishness/never to be repeated, "one more crab") - it was up to the surface! I also agree, "My pony isn't for anyone but me. It's attached to my primary tank in the back with the regulator bungeed around my neck. If I have a buddy out of air, that's what my octo is for." It is a consideration that a panicked OOA diver may grab my any of my regs from me.
I'll explain now why I use a full sized gauge. I'm 59 years old, and my eyesight used to be excellent, when I was young - not now, so I have a full sized gauge that may be easily read. I also found that I was a bit anxious, even about my pony air, when I was low on air in my "one more crab" foolishness. To be able to watch the air in a primary reg failure (or something else) even if coming up and possibly wanting to do a safety stop, is important to me to know where my air is. Also, especially since my pony is back mounted, I want to know that I haven't been unknowingly bleeding air out of my backup system. I found it easy to just add a longer hose on my pony's air gauge (which is attached parallel to the primary reg's hose) so that it can be read easily.
I also want to add, in my "one more crab" stupidity, I found that it can be difficult to orally add air to one's bcd in rough surface water - better to add some when down below - especially if one has a full load of crabs and has dumped out all the air to grab just one more!
Good gas management, stick to your plan (no matter how big that crab/lobster is), thinking through and practicing emergency plans, are all so important. I'm glad to be alive to share with all who will listen.
DrDaddy