Forget about that 140 CF cylinder, heavens knows what that is.
First be patient with yourself different divers get their breathing and consumption to settle down at different rates. That being said it's highly likely that you will never match a female buddy whose weight is half yours. It's just a matter of life sciences and physics.
My wife and I are new divers and she is the bigger user at this point in time but she is closing the gap. Give it time. If you're getting nice dives there is no shame in one diver coming back with extra air. In fact it's a nice contingency!
If you want to move up I'd consider a steel cylinder that remains neutral or heavier when empty. This will get some un-needed weight off your belt and lower your overall mass while giving you more air to work with. The PST-E7-100 is a darling with a going price around $350. Remember to evaluate weight and buoyancy independenty when making a choice, they each have implications.
You are also correct that you need to end up with enough ditchable weight to get out of trouble. In a 3mm suit the buoyancy loss is minimal. If you see yourself going to 5mm or 7mm the weight you will want ditchable to make up for lost suit buoyancy in the event of a BC failure will climb. That will be easy to achineve since you will be wearing more to begin with. You just don't want to incorporate too much of it into the tank. Being in Ohio I see heavier wetsuits in your future so steel starts to make even more sense.
Finally, I almost forgot to mention this one.... Between scuba outings get out there and skin dive. It will boost your comfort in the water, let you establish good oral breathing (deep & steady) , give you a good cardio workout, tone your legs for swimming and slash your air usage. I honestly belive that is what made a huge difference for me. It's a great way to scout future dive sites!
Pete
DavidHickey:
I'm an admitted Hoover and was trying figure out a way to get more bottom time. I stopped by my LDS at lunch today and spoke with the owner about a larger tank. He told me going up to a 100cf would probably run me about 350.00 but he wasn't really sure as the prices have been going up and he hadn't ordered any in awhile. BUT he said he had something in back that I might be interested in. "Kinda felt like he saw me coming!!!!" He has a Aluminum 140cf tank that needs a current Hydro which he said runs 32.00 He said it belongs to one of his customers who wants to get rid of it. He wants 200.00 for it. He said new it was around 500.00 Sounded great at first but he was saying something about it being almost 20 pounds negative? In my 3mm i usually only use 12 pounds. Any thoughts on jumping to a tank this big? I thought an 80cf Aluminum was 6 pounds negative, so I find it hard to believe a 140 would be 20 pounds negative. Anyhow being a newby it sounds great but there has to be draw backs or everyone would have one!!! I realize its probably heavier than the 80cf tanks but being as my Fiancee is 120 and handles her 80cf and I'm 245 I figure I could probably handle the extra weight. Any thoughts would be appreciated
David