Congrats on the 100th dive.
Allow me to make a constructive comment: if you are running out of air in an hour at 60 feet, that tells me you are overweighted. I do realize that the cold water does add to exertion, increasing air usage. However, overweighting really does increase your gas usage and you can make a big difference in your air consumption by correcting your weighting. Being overweighted, you are adding and dumping air from your BC, rather than once or twice, and also overcompensating in your breathing having to rise and fall to compensate. On a recent warm water trip (gasp), I used the same weight as in the past, but I was still sinking when I should be neutral. With 500 psi in the tank and deflated BC, I held a normal breath at the surface and floated almost at eye level, but ever so slightly lower. I took a whole kilo off (2.2 lbs!), dropping to 4 kilos total, and as soon as I hit the water on the next dive I could tell I was perfect. After that I could hover motionless. I touched my BC twice on the dives: add a quick shot of air at depth at the beginning, dump all that air at about 2000 lbs after the tank became slightly more buoyant. I mention the actual weight numbers to show that a big weight difference made a small difference in my float at surface test but a huge difference in how netutral I was.
Here's how to tell, besides the float at eye level test: if you have to move at all, at all, to keep yourself from sinking, you're overweighted. Schedule a dive to just work on your weighting. You have to have a place not affected by surge because it would be hard to distinguish. Maybe even a boat dive. The weighting will always be the same if you dive in this area. From then on, you're good and your air consumption won't be affected by that. You can breathe normally and not have to do all this rise and fall stuff. Next is work on what I call "sleep breathing"...
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