Steel 100's used / nitrox

[billt4sf]

I think I want to buy two steel 100 tanks for use with nitrox. I am a big guy, an air hog, and with the dry suit here in NorCal I carry about 30 lbs of weight. So rather than carry more weight with an AL tank, I am thinking that a smart thing to do would be to buy the steel ones (which I can get sometimes when renting but not always, and not with nitrox which is what I strongly prefer -- less fatigue after the dives).

I'm not sure how to go about this. There are so many terms, codes, and things I don't know about. Is there a good primer on tanks? What restrictions / prices should I look for? Does it have to be recertified, inspected, or "hydro" (what is that?) ? Can it be shipped or should I get it locally?

My LDS quoted me $369. I think that was for one tank? Way out of my price range.

Thanks,

Bill

 

[Ouvea]

Bill:

The High Pressure 100 Cubic Feet Steel Tanks are quite popular in our area. They provide a great deal of air and are not too heavy for even those of shorter stature. I'm 5'5, weigh about 130-135lbs and can manage this tank on any shore dive. You might want to look on craigslist and see if anyone is selling them. I seem to recall someone in either Watsonville or Castroville selling several pre-owned tanks for around $250 each. However, that listing dates to late last year.

My Atomic regulator can handle the 3400 PSI working pressure without the need to convert to DIN. However, make sure that your regulator can handle the added pressure (I'm certain most can but it's better safe than sorry). You might also want to consider a Low Pressure 95 cft, which do not cost as much.

If you decided to mail-order the tank, it will arrive with the valve dismounted. Your LDS will have to perform a visual inspection, before refilling. Factor that into the total cost of the tank. Also, make sure you look at each tank's buoyancy characteristics. It's as important as the internal volume at its working pressure.

Here's a great write-up on the differences between tanks. How to Select a SCUBA Tank - Dive Gear Express

 

[halocline]

You could do some research on tanks; there's a good chapter on tanks in Vance Harlow's regulator repair book if you can get a hold of that. In the U.S. all compressed gas cylinders have to be hydro tested, which means filled with water and highly pressurized to measure structural integrity, every five years. All dive shops require annual visual inspection to fill scuba tanks.

As far as what to buy, the best thing is to rent a few different tanks and then buy whatever size you like best. The SP (special permit) 3442 PSI 100cft tanks are really popular, but you might want an even bigger tank.

If you're noticing significantly more fatigue with air than with nitrox, you might try diving with air but extending your safety stops (I often do 10 minutes on deep repetitive dives) and really slow your ascents. If you have a computer with a color-coded N2 loading bar, wait for it to go to green before surfacing on every dive. You might find that this takes care of the fatigue as well as using nitrox.

 

[billt4sf]

Here's a great write-up on the differences between tanks. How to Select a SCUBA Tank - Dive Gear Express

That's a great write-up and JUST what I was looking for! Thanks. I think I will go with an steel HP100 for 3442 fills. Now I have a pretty good idea what that means. My wife and I will then run out of air at about the same time.

As far as fatigue, I'll try the 10-min safety stop but I am doubtful. We are novice divers and typically only go to 40 - 60 ft.

- Bill

---------- Post added February 22nd, 2013 at 07:41 AM ----------

If I bought a used tank, must I / should I have it hydro tested as well as visually inspected? Does anyone know off hand how much that might cost? It sounds like it might significantly reduce the savings of buying a used tank.

- Bill

 

[JohnN]

That's a great write-up and JUST what I was looking for! Thanks. I think I will go with an steel HP100 for 3442 fills. Now I have a pretty good idea what that means. My wife and I will then run out of air at about the same time.

As far as fatigue, I'll try the 10-min safety stop but I am doubtful. We are novice divers and typically only go to 40 - 60 ft.

- Bill

---------- Post added February 22nd, 2013 at 07:41 AM ----------

If I bought a used tank, must I / should I have it hydro tested as well as visually inspected? Does anyone know off hand how much that might cost? It sounds like it might significantly reduce the savings of buying a used tank.

- Bill

One last bit, if you're planning on diving EAN (Nitrox), check with your LDS and see if they have banked gas or do partial pressure fills.

If they do partial pressure fills, they are going to require the tanks and valve to be O2 clean. If you're buying new, this is not a problem, if you're buying used, you need to factor this into your price (in addition to visual and hydro)

If you are a big guy, you might consider going to HP120's.

 

[Peter_C]

Bill and I have been going back and forth over email too. To add a little more information in, Bill is around 6' 6" and uses an HP100 diving 30-40 depths with about 45 minutes of bottom time. Do others feel the HP100 is the right tank for him? Or do you have another recommendation?

Hydro only needs to be done every 5 years, and it will be stamped with a date the last time it was done. Cost is $15 from a fire extinguisher place. LDS charge over $40 and send them to the same fire extinguisher place. Just ask the hydro shop for a vis sticker. Visuals are not a big deal, but I have no idea what a local shop charges. I would recommend vis'ing them when purchasing if possible. Easy enough to drain them and look in with a bright flashlight. Of course some dive shops won't refill a completely empty tank until they get to charge for a vis.

 

[maniago]

Bill and I have been going back and forth over email too. To add a little more information in, Bill is around 6' 6" and uses an HP100 diving 30-40 depths with about 45 minutes of bottom time. Do others feel the HP100 is the right tank for him? Or do you have another recommendation?

That's funny you should ask that, cause as I was reading the thread, my thought was "this guy is going to air out on a 100". I'm the avg 5'8" 165 and I also dive a single Worthington 100 steel. I can get up to 65mins on a tank, or as little as 20, depth depending. That said, unless he's going to go double 100's, I'd think he should consider a 119, especially with his height. He might be able to handle the massive 130s, but I can't recall anyone I know liking them really...and I've heard their extra diameter can be an issue with boat racks.

As for his wife, he'll out breathe her on a 100 easy. I do by about 1/3 and we're same height, same weight, first year divers. Women just don't have the same lung capacity as guys. Its an advantage for them in scuba, IMHO.

Something to consider, I bought our tanks this past year, and I really wanted 119s. The only reason I didn't is my wife can't handle the 119 weight and I wanted to make it all seemless between us. So we got 4 100s, and only dive them as singles. That makes 2 tank diving cake, and fits in the trunk of the car with all our gear easy. Its was by far the right choice for us, and I'm still amazed I got that "conservative" decision right. Happy wife is a happy husband.

 

[Peter_C]

I'd think he should consider a 119, especially with his height. He might be able to handle the massive 130s, but I can't recall anyone I know liking them really...and I've heard their extra diameter can be an issue with boat racks.

The HP119's are the same diameter as the HP130's @ 8.0" . HP120's are narrow 7.25" and longer which work perfect for taller people, and yes they fit boat racks. Although you can always just strap an 8" tank in somewhere.

I like my single HP130's and do not use my single HP100's ever, except I do use my set of double HP100's fairly often. I know lots of people that love their HP130's and even women. I also know folks that love their HP120's and tons that love their HP100's. Can't think of anyone that loves their AL80's as a primary tank...

Massive is not the key word for a person that is 6'6", as they are massive. The weight difference is marginal when the tanks are empty at only 1 pound difference from the HP119 to the HP130. The difference is in gas weight when full and that you want, and it will be far less when returning to the surface.

X-Series Steel SCUBA Tanks by Worthington Cylinders - Dive Gear Express

 

[maniago]

The HP119's are the same diameter as the HP130's @ 8.0"

Ack. Right you are. I was thinking length of the 119 when I was doing my research since we're both short people, and its basically a 100 in length.

For me and the wife, its the full weight thats an issue as we dive from shore. Boat diving, yeah no big diff, except the haul to the boat from the car.....

---------- Post added February 22nd, 2013 at 01:55 PM ----------

Hydro only needs to be done every 5 years, and it will be stamped with a date the last time it was done. Cost is $15 from a fire extinguisher place. LDS charge over $40 and send them to the same fire extinguisher place. Just ask the hydro shop for a vis sticker. Visuals are not a big deal, but I have no idea what a local shop charges. I would recommend vis'ing them when purchasing if possible. Easy enough to drain them and look in with a bright flashlight. Of course some dive shops won't refill a completely empty tank until they get to charge for a vis.

I took the VIP class since it was more cost effective to do my own vips with 4 tanks. That said, not all Hydro places will give you VIP, as VIP is a human inspection, and hydro is a machine inspection, so to speak. We have a hydro place here and that's all they do - you get the tanks back wet. I can't speak for fire extinguisher places; I'd want to see their hydro machine, certs, and ask about their set up between life support and non-life support tanks. It maybe that they do hydros for all types of tanks and their techs know their job, which would be fine.

 

[halocline]

Every hydro shop in the country does fire extinguishers; it's probably 75% of their business. They also do welding tanks, CO2 tanks, and breathing gas tanks for both scuba and SCBA. And medical O2 tanks. So they all have the same certification. Do they all know a lot about the particulars of scuba tanks, like the plus rating rules for 3AA tanks? Not a chance.

---------- Post added February 22nd, 2013 at 06:13 PM ----------

As far as fatigue, I'll try the 10-min safety stop but I am doubtful. We are novice divers and typically only go to 40 - 60 ft.

I think the fact that you're novice divers improves your chances of feeling the benefit from long stops and VERY slow ascents. I believe that a contributor to post-dive fatigue is how much N2 you surface with. The long stop, (actually I do a 3 min stop at a bit deeper than 15 ft, closer to 20, then 5-7 min at 10 ft) has been shown to very efficiently off gas N2 in non-decompression diving. Then take a full minute to surface, that's very slow. I'll bet you'll be amazed at how much better you feel, particularly on multiple-dive days.

The bit about using nitrox in the tank does add some complication, and you should try to learn as much as possible about it. The reason it's complicated is because there are no clear rules that everyone adheres to. The safest thing in terms of always being able to get a fill is to have the tank O2 cleaned and only use nitrox in it. That's not really necessary for most nitrox fills (banked and/or continuous blend) but some shops simply will not put nitrox in a tank that is not labeled as 'nitrox' which really means O2 clean. You'll be amazed at how uninformed some dive shop employees and fillers can be. I had a tank filler almost refuse to put banked nitrox in my tank because it did not have a green 'nitrox' sticker or a green valve dust cap. So I put a green cap on it, and he filled it. (this was on a charter). True story......