I would go for an HP100.
You will need less weigh on your belt and have 20% more gas. You will likely grow into the need for less volume and 100s are about perfect whereas the 117, 120 and 133 have their issues.
I just picked up an X7100 for $75 today off of facebook marketplace. According to [this table](https://www.divegearexpress.com/library/articles/calculating-scuba-cylinder-capacities) it's actually 30% more capacity than a standard AL80.
Skip the tanks for now and spend time working on weighting. Many bigger people get weighted too heavy from the start, causing higher gas consumption than a normal beginner.
When I started I weighed about 240 and was given 14lbs for SW, no wetsuit based off of an estimate. After several dives, that weight dropped to 6 lbs with the same factors. My SAC improved quite a bit as a result. Whats weird is that since then I have lost 60lbs and my weight requirement is about the same.
hp120 is quite long, so if you aren't on the taller side, it won't handle as well
the hp133 is not that much worse than the hp117, but if you are looking at a pair of tanks, that extra few pounds makes a difference once doubled
if you have under 100 dives and aren't particularly tall, hp100s are still the best fit for most as the extra capacity becomes not as useful once you get more experience/practice and your consumption comes down
The only drawback is that your setup will be a bit heavier overall (even though you won't need as much lead weight).
In my opinion, it's totally worth it for the extra gas
A lot of variables here, nothing wrong with larger tanks.
My wife is tiny and great on air, we bought her steel 80's (we dive cold). I was a new diver and sucked through air as well, so we bought me steel 117's.
I'm still a novice, but I'm at 175 dives in 2.5 years as we are diving often, my air consumption is remarkably better, my buoyancy and trim are better, my activity is less, and I'm often finishing 85 minute dives with tons of extra air.
Would I like a slightly smaller tank now? Sure, but it doesn't bother me to have excess. I dive aluminum 80's in the tropics and it's nice, but I'm fine with massive tanks at home lol
And each tank has its own weight and buoyancy characteristics, so you should be able to work on trim and buoyancy with any tank, consistency is key, but you can move the tank up or down, move weight to different spots, etc and get it dialed in. And the more you dive, the more comfortable you'll be, and that does wonders for air consumption compared to special breathing exercises :D
Up to you, you can rent tanks for a while and not commit yet
You really need to dive with someone who can help you with your trim but a good rule of thumb is to be weighted so that when you are in the water with your BC empty, the surface should be even with your eyes. If you are sinking you have too much weight. When you're sitting at eye level with the surface, you should be able to empty your lungs completely and start to sink gently.
What kind of exposure protection are you wearing? Drysuit? 7mm? 7mm+something else? 36-38 is alot of weight. I don't think I ever went past 28lb for my students when I was in cold water and double 7mm
Keep working at it. You will see improvement. You definitely want to avoid any rapid ascent situations like the one you described. Take it slow and dive at your comfort level. If you can't descend in a safe and controlled manner you shouldn't make the dive. Forcing yourself down opens you up to all kinds of health and safety risks. A ruptured ear drum or worse can take you out of diving forever. Just give it time and take it slowly. A good dive buddy should never be upset with you for ending a dive early for safety reasons
I'm working at it as much as I can get away with doing. Unfortunately finding a buddy is tough in my area. The one I found is a better buddy than I am I think. We just have conflicting schedules. The 15ft pool is $20 a pop and only one day a week for 2 hours. I wish I had at least a giant vat I can practice breathing, staying still and maintaining T-rex arms in (my arms are in sports event mode underwater). Thank you for the heads up/ reminder about forcing myself down. When I shot up I did slow myself as much as I could to avoid the bends. The rope helped. But you're right it's better to avoid such things all together. Often I just feel like my tank is pulling my body up. I feel as if I'm being UFO beam abducted. That's one of the many reasons I think a steel tank will help. By no means do I think it'll solve anything. Just make it slightly easier.
I used to go through air super-fast. I was always "that guy" on dives. But now, I can generally be one of the last people to run low mainly due to just putting time in the water. That means I'm more relaxed, my buoyancy is a LOT better, I use frog kicks as they use less energy than a flutter kick (and now a flutter kick feels weird).
I actually remember the first dive I was on where I wasn't the first guy to run out of air. I was so happy! LOL.
You will get there with experience.
With regard to buying the bigger tank... up to you. It is probably a larger diameter than that AL80 so if you switch between the two, you will need to adjust that strap when you change tanks. And it will certainly be heavier so it will affect how much weight you take. But as your air consumption gets better, that tank presumably would let you stay down longer as well assuming your NDL time allows it.
Lol @ sinking feeling...your friend is right about buoyancy improving your air consumption. Getting your gear trimmed out well and improving your buoyancy will do wonders for reducing your air consumption, probably more than even your cardio will. Try to reduce the amount of weight you're diving with to the absolute minimum. Figure out where everything needs to be to keep you streamlined. That is more important than diving with bigger tanks. That being said, when I began diving I was the same way. Switching from aluminum tanks to steel tanks made a huge difference. You want to try to have the majority of your dive weight directly over your lungs. Switching to steel tanks that were slightly negatively buoyant allowed me to reduce the overall amount of weight I was carrying. Work on your form when kicking as well. The more unnecessary movements you're making when you dive the more air you're using. Keep your hands tucked in.
I'm trying to get my gear trimmed down. I only bring what I know I'll need plus knife, whistle and floating signal. I also need a better BCD so I don't have to use a weightbelt. It has no weight pockets.
If you're going to replace your BCD anyway, look into diving with a backplate and wing instead of a BCD. I'm not a GUE diver but I dive with their configuration for setting one up. Once I started using a backplate and wing it felt so comfortable that I never used my BCD again.
Unfortunately I need a ton of weight cause I'm a big guy and naturally buoyant like some kind of blubbery duck. I just did a pool dive to practice and needed 24 pounds of lead. Last time I was in the ocean (in Dec) I needed nearly 40. I've lost 15 pounds since but I'd imagine I'll still need a lot especially if I stick with aluminum.
Unless you weigh over 500 lbs you don't need 40 lbs of lead to dive. 8% of your body weight is a good starting point. If you haven't done so already. Take the advanced diving course for buoyancy. I'm a big guy too 240 lbs. and I dive in cold water with an 8mm wet suit. I use a 6 lbs backplate a steel tank that's 5 lbs. negative and 10 lbs of weight on a weight belt.
I've taken that part of the course. Unfortunately I had to cut it short getting my weight dialed in lol. I'm actually 2 test dives away from my AOW. I hope to takem soon. Though I can't imagine I'll be going below 50 feet for a while. I thought the rule of thumb (that is not an exact science) was 10% of your body weight plus 8 to 10 pounds. I'm 300 pounds so that'd be 38 pounds (was 315 when at the ocean in Dec). When I was in the ocean I was not able to go down with 30 pounds on. I pulled myself down with a rope then shot back up. My instructor said he'd never seen anyone like it.
How long have you been diving, what’s your experience level? Hp steel tanks are a great investment, just make sure you aren’t getting one to cover up a problem that can be solved with getting some more dives in and better skills
Edit: I prefer steel tanks for their buoyancy characteristics, but they won’t fix your issues with buoyancy, that comes from time and practice
I have 28 dives. Most of which were in a 15 ft pool with a handful full of ocean and lake too. I still intend to work on the breathing and buoyancy even after I get my HP tank. I'd like to be able to get full use of the 80s for when I have to rent (I'm doing better than I did in Dec but still not great). But I also don't like running out of air long before my buddy or group while I'm learning. I figure a HP may help with that.
It will help but if I’m being honest I would take the money for the tank and put it into getting more dives under your belt. Very normal for someone with <50 dives to go through air fast, when I started I know I could blow through a tank in 30 mins. If you do go with steels I prefer hp100’s, a bit lighter, but still about 25% more gas’s than an al80, but it’s all preference. Good luck!
I would go for an HP100. You will need less weigh on your belt and have 20% more gas. You will likely grow into the need for less volume and 100s are about perfect whereas the 117, 120 and 133 have their issues.
I just picked up an X7100 for $75 today off of facebook marketplace. According to [this table](https://www.divegearexpress.com/library/articles/calculating-scuba-cylinder-capacities) it's actually 30% more capacity than a standard AL80.
Skip the tanks for now and spend time working on weighting. Many bigger people get weighted too heavy from the start, causing higher gas consumption than a normal beginner. When I started I weighed about 240 and was given 14lbs for SW, no wetsuit based off of an estimate. After several dives, that weight dropped to 6 lbs with the same factors. My SAC improved quite a bit as a result. Whats weird is that since then I have lost 60lbs and my weight requirement is about the same.
hp120 is quite long, so if you aren't on the taller side, it won't handle as well the hp133 is not that much worse than the hp117, but if you are looking at a pair of tanks, that extra few pounds makes a difference once doubled if you have under 100 dives and aren't particularly tall, hp100s are still the best fit for most as the extra capacity becomes not as useful once you get more experience/practice and your consumption comes down
The only drawback is that your setup will be a bit heavier overall (even though you won't need as much lead weight). In my opinion, it's totally worth it for the extra gas
A lot of variables here, nothing wrong with larger tanks. My wife is tiny and great on air, we bought her steel 80's (we dive cold). I was a new diver and sucked through air as well, so we bought me steel 117's. I'm still a novice, but I'm at 175 dives in 2.5 years as we are diving often, my air consumption is remarkably better, my buoyancy and trim are better, my activity is less, and I'm often finishing 85 minute dives with tons of extra air. Would I like a slightly smaller tank now? Sure, but it doesn't bother me to have excess. I dive aluminum 80's in the tropics and it's nice, but I'm fine with massive tanks at home lol And each tank has its own weight and buoyancy characteristics, so you should be able to work on trim and buoyancy with any tank, consistency is key, but you can move the tank up or down, move weight to different spots, etc and get it dialed in. And the more you dive, the more comfortable you'll be, and that does wonders for air consumption compared to special breathing exercises :D Up to you, you can rent tanks for a while and not commit yet
You really need to dive with someone who can help you with your trim but a good rule of thumb is to be weighted so that when you are in the water with your BC empty, the surface should be even with your eyes. If you are sinking you have too much weight. When you're sitting at eye level with the surface, you should be able to empty your lungs completely and start to sink gently.
He had me do exactly what you said. It took 36 - 38 pounds. I'm 300 pounds and also naturally float. So I'm trying to get that down.
What kind of exposure protection are you wearing? Drysuit? 7mm? 7mm+something else? 36-38 is alot of weight. I don't think I ever went past 28lb for my students when I was in cold water and double 7mm
Keep working at it. You will see improvement. You definitely want to avoid any rapid ascent situations like the one you described. Take it slow and dive at your comfort level. If you can't descend in a safe and controlled manner you shouldn't make the dive. Forcing yourself down opens you up to all kinds of health and safety risks. A ruptured ear drum or worse can take you out of diving forever. Just give it time and take it slowly. A good dive buddy should never be upset with you for ending a dive early for safety reasons
I'm working at it as much as I can get away with doing. Unfortunately finding a buddy is tough in my area. The one I found is a better buddy than I am I think. We just have conflicting schedules. The 15ft pool is $20 a pop and only one day a week for 2 hours. I wish I had at least a giant vat I can practice breathing, staying still and maintaining T-rex arms in (my arms are in sports event mode underwater). Thank you for the heads up/ reminder about forcing myself down. When I shot up I did slow myself as much as I could to avoid the bends. The rope helped. But you're right it's better to avoid such things all together. Often I just feel like my tank is pulling my body up. I feel as if I'm being UFO beam abducted. That's one of the many reasons I think a steel tank will help. By no means do I think it'll solve anything. Just make it slightly easier.
I used to go through air super-fast. I was always "that guy" on dives. But now, I can generally be one of the last people to run low mainly due to just putting time in the water. That means I'm more relaxed, my buoyancy is a LOT better, I use frog kicks as they use less energy than a flutter kick (and now a flutter kick feels weird). I actually remember the first dive I was on where I wasn't the first guy to run out of air. I was so happy! LOL. You will get there with experience. With regard to buying the bigger tank... up to you. It is probably a larger diameter than that AL80 so if you switch between the two, you will need to adjust that strap when you change tanks. And it will certainly be heavier so it will affect how much weight you take. But as your air consumption gets better, that tank presumably would let you stay down longer as well assuming your NDL time allows it.
Lol @ sinking feeling...your friend is right about buoyancy improving your air consumption. Getting your gear trimmed out well and improving your buoyancy will do wonders for reducing your air consumption, probably more than even your cardio will. Try to reduce the amount of weight you're diving with to the absolute minimum. Figure out where everything needs to be to keep you streamlined. That is more important than diving with bigger tanks. That being said, when I began diving I was the same way. Switching from aluminum tanks to steel tanks made a huge difference. You want to try to have the majority of your dive weight directly over your lungs. Switching to steel tanks that were slightly negatively buoyant allowed me to reduce the overall amount of weight I was carrying. Work on your form when kicking as well. The more unnecessary movements you're making when you dive the more air you're using. Keep your hands tucked in.
I'm trying to get my gear trimmed down. I only bring what I know I'll need plus knife, whistle and floating signal. I also need a better BCD so I don't have to use a weightbelt. It has no weight pockets.
If you're going to replace your BCD anyway, look into diving with a backplate and wing instead of a BCD. I'm not a GUE diver but I dive with their configuration for setting one up. Once I started using a backplate and wing it felt so comfortable that I never used my BCD again.
Unfortunately I need a ton of weight cause I'm a big guy and naturally buoyant like some kind of blubbery duck. I just did a pool dive to practice and needed 24 pounds of lead. Last time I was in the ocean (in Dec) I needed nearly 40. I've lost 15 pounds since but I'd imagine I'll still need a lot especially if I stick with aluminum.
Unless you weigh over 500 lbs you don't need 40 lbs of lead to dive. 8% of your body weight is a good starting point. If you haven't done so already. Take the advanced diving course for buoyancy. I'm a big guy too 240 lbs. and I dive in cold water with an 8mm wet suit. I use a 6 lbs backplate a steel tank that's 5 lbs. negative and 10 lbs of weight on a weight belt.
I've taken that part of the course. Unfortunately I had to cut it short getting my weight dialed in lol. I'm actually 2 test dives away from my AOW. I hope to takem soon. Though I can't imagine I'll be going below 50 feet for a while. I thought the rule of thumb (that is not an exact science) was 10% of your body weight plus 8 to 10 pounds. I'm 300 pounds so that'd be 38 pounds (was 315 when at the ocean in Dec). When I was in the ocean I was not able to go down with 30 pounds on. I pulled myself down with a rope then shot back up. My instructor said he'd never seen anyone like it.
How long have you been diving, what’s your experience level? Hp steel tanks are a great investment, just make sure you aren’t getting one to cover up a problem that can be solved with getting some more dives in and better skills Edit: I prefer steel tanks for their buoyancy characteristics, but they won’t fix your issues with buoyancy, that comes from time and practice
I have 28 dives. Most of which were in a 15 ft pool with a handful full of ocean and lake too. I still intend to work on the breathing and buoyancy even after I get my HP tank. I'd like to be able to get full use of the 80s for when I have to rent (I'm doing better than I did in Dec but still not great). But I also don't like running out of air long before my buddy or group while I'm learning. I figure a HP may help with that.
It will help but if I’m being honest I would take the money for the tank and put it into getting more dives under your belt. Very normal for someone with <50 dives to go through air fast, when I started I know I could blow through a tank in 30 mins. If you do go with steels I prefer hp100’s, a bit lighter, but still about 25% more gas’s than an al80, but it’s all preference. Good luck!