What's the most popular tank size?

[vanDavid]

I've placed the order for my steel HP100s and can't wait to try 'em out. I've also made the switch to DIN.

I got used to having lots of gas on my back after diving with Aldora Divers in Cozumel this past November. We used steel HP120s and never had a BT less than 60 minutes. Very nice. Great dive op.

 

[Matt S.]

Great thread... what length of tanks should I be looking at, being 5' 9"? My wife is 5' 4". We are both drysuit divers and air hogs, so I was also thinking about a HP 100 or 120. (We have DIN regs.) However, I had not considered the length issue.

 

[somewhereinla]

Everything is starting to make sense... So I should get no less than 100CF. I was always leaning towards steal, so no surprise there. No HP or LP? I did read about the adventages and disadventages for both... But what's more popular? It seems that LP is more convenient...
I doubt I will go Nitrox anytime soon, and for the next year or so would label myself as a recreational diver.

Oh, and by the way, thanks you for the great feedback. I am learning a lot.

 

[RonFrank]

Everything is starting to make sense... So I should get no less than 100CF.

I'm not sure saying that no less the 100CF is the perfect tank for all dives. On a shallow reef, I can stay down an hour on +/- 1000 psi with an AL80. In that situation a Steel HP 100 would allow two shallow reef dives on one tank for a trip, however I rarely do two shallow reef dives on one boat trip. I'd be using two tanks for two dives, and I'd be coming up with 2000psi in one tank if using a HP steel, but that is not really enough to do two dives if one is deep, and one is shallow. I could use a steel HP 100 on a deep dive, and then an AL80 for the shallow, but I really don't generally need 100CF of air for either, and 100CF is not enough for both.

I dove Coz for 8 days in January, and the only time I used and wanted 100CF of air was on the morning we did a dive to 135'. In that case the 100CF was the right choice. However the rest of the week I was able to do hour long dives at depths as deep as 100 feet with multi-level profiles on AL80's. Most divers on the boat used AL80's, and we were doing four dives a day, two on Nitrox, two on air for the most part.

So again, it really depends on the diving you plan on doing, how deep, and if the profile is flat, or multi-level. If you routinely do flat 80' profiles with Nitrox an HP 100 is definitely the right choice. If you are doing flat profiles at 80' using air the real question becomes can you get 25 minutes at 80' with deep, and shallow SS's on an AL80.

Most divers hit their NDL before they run out of air, so a HP Steel 100 is just unused air, not a bad thing, but there is a reason most divers dive AL80's, and that reason is that because it's enough air for most rec divers to hit their NDL long before they run out of air. Another factor is can you find an LDS that will fill the HP's to 3500psi, cause many will not. Likewise some will overfill the LP steel to 3000psi which is not really dangerous, but may lessen the life of the tank.

Certainly there are other factors like turn times, and a safety margin for your buddy. However if you are good breathers, and only doing rec no overhead diving those factors can be adjusted a bit even if some tech divers may disagree with this statement.

IMO if money is not an object, by all means run out and purchase two or even three HP Steel 100's. However realize you can purchase two AL80's for not a lot more than the cost of one HP100. Steel tanks also weight more, but have negative buoyancy characteristics that some divers like. OTOH, there are neutral Alum tanks on the market as well.

If I moved to FL tomorrow, I'd be in the market for HP 100's as I love to dive Jupiter, and it's a flat deep profile that I can dive using EANX36. However I'd keep my 80's, and maybe even put them in a double config for other types of diving including shallow reefs, or even wreck/reef combinations.

Confusing, isn't it! Well, not really, but until you have more diving under your belt, you may not be able to really judge what is going to work best for you even with all this GREAT advice!

 

[Stu S.]

If I moved to FL tomorrow, I'd be in the market for HP 100's as I love to dive Jupiter, and it's a flat deep profile that I can dive using EANX36.

Ron's explanation is a good one. Jupiter diving is a perfect example. What tells you it is time to head for the surface? Is it your tank gauge or your computer? I was borrowing a 120 a couple of years ago and would up with 1300 psi in the cylinder after the dive. My 80 cu. footer ran low with time left on the computer. With 100 cu. ft. of Nitrox 36, both the computer and tank gauge say "time to go" at the same time.

I have been using an LP 85 filled to 3,200 psi. That's about 100 cu. ft. It is easy to dive with. Recently, two locations told me they won't fill it beyond 2640 psi. This trend may continue, so consider that when you make choices.

See you at Jupiter.

 

[Mossman]

A couple of thoughts. First, unless you dive quite a bit, is a tank really something worth having? Between the purchase price and the anual cost of vips and hydros, it can take a lot of diving to break even renting tanks. If you do feel you can justify the cost of ownership, then you are really going to need at least 2. It is nice having a tank ready when you want it but for a lot of divers it's the last piece of equipment they should consider buying.

There's no real need for somewhereinla to have more than one tank unless he's doing multiple beach dives.

 

[redrover]

Great thread... what length of tanks should I be looking at, being 5' 9"? My wife is 5' 4". We are both drysuit divers and air hogs, so I was also thinking about a HP 100 or 120. (We have DIN regs.) However, I had not considered the length issue.

I don’t know about the drysuit thing but at almost 5’4” a AL 80 does not fit me. I’ve got bitty little AL 50’s that are perfect, on my own I’m good for over an hour. But they are a problem when chasing power swimming buddies with water heaters, my SAC drops and cuts their dive short.
I’ve dove a 120, egad! Doable but not very manageable for shore.
I’ve got steel HP 80’s that are working out very well. Wish I could test a HP 100, but I suspect it would be too long for me.
My impression is us shorter folk have less leeway with tank positioning regarding trim. And I’m thinking there are possibly significant aspects concerning fat distribution. So far everything I’ve read of trim adjustment solutions don’t work for my body type and length.
I strongly encourage wifey to test out tanks. Just a few inches can really make a difference. These guys have the best (I’ve found) source for tank comparison.

 

[Colliam7]

HP Steel, 120 - 130cf, DIN valve

In a separate, long-running SB thread asking, 'What gear do you most regret buying?' about 10% of posts mentioned regret about buying (yoke) AL80 tanks. AL80s are fine tanks, they are common, popular, functional, reasonable weight, etc., etc. But, many people (myself included, along with some respondents here) seem to find as they dive more that they want more air, or more weight, or a DIN connection, or all three. More air gives you more bottom time per dive. I would rather have to ascend because I am approaching the NDL, than because I am low on air. With your size, a bigger, heavier tank should not be an issue. If you find you dive quite a bit, you will probably appreciate the utility of a steel 120 or 130. If you happen to like diving so much that you go toward technical, you are more likely to want to double up a 120 or 130, than an AL80. Even if you ultimately decide that diving is not a priority for you, steel DIN 120-130s have good resale value.

Just my opinion (aka personal preference)

 

[Tom Winters]

... what length of tanks should I be looking at, being 5' 9"? My wife is 5' 4". We are both drysuit divers and air hogs, so I was also thinking about a HP 100 or 120. (We have DIN regs.) However, I had not considered the length issue.

An awesome rig for your wife, if she is in a little bit of shape, is twinned LP66's. Leetle tiny things. There's a lady in West Palm who dives a single LP66, is incredibly efficient on air, and always returns with gas in her tank.
One of the tech guys down here uses twinned LP66's, and he's a big guy. But he could fill his tanks to 4500psi too.
At 5'9", an HP120 is going to smack you either in the head or the butt - your choice depending on where you position it. My wife worships her HP100's. They sure are light compared to my LP125's and LP108's.
I have two different makes of LP85s which I consider a great tank for twins. Maybe the best.

 

[CompuDude]

If you're diving SoCal, a guy your size is going to want a nice big tank. The HP100 is nearly perfect as an alternative to the Aluminum 80 everyone learns on. (Note the answer might be different for a significantly smaller person or a warm water diver.) It beats out the aluminum tank in every single way (except price).

Here in SoCal I see Worthington's as being the best option. The hot dipped galvanized finish holds up well to salt water. The faber's are heavier... perhaps too heavy, some might say... and painted, which I don't trust as much as the galvanized coating. Still good tanks, but I prefer the Worthingtons.

Get the biggest tank you're comfortable with: As long as you're not hurting yourself trying to carry it, it's tough to have "too much" air when diving. I'd rather not use a lot of my tank every dive than not have enough, and what if your buddy has a problem? More gas in your tank = more time to resolve the problem with both of you breathing from it.

I am very happy with my singles kit right now, which consists of three Worthingtons: two HP100s and one HP119 for those times when longer bottom times (or shorter walks) justify the increased on-land weight. I'm 6'3" 190.