Using a HP 120 instead of a HP 80?

[PvtStash]

Pro 120 cu ft of gas vs 77 cu ft.
Con for the 120 is that some shops don't fill to the full 3400 to 3500 .

I'm a big guy, jus' under 6' 3", and was thinking that when I get My tanks I'd go with the 120's , but this comment about 120's being shortchanged on air fills rankles me a bit... or maybe it doesnt...

It all depends on how the fill is being Charged, when you get charged to fill your tank are you charged based on its size? (80, 100, 120) or are you charged for the amount of Actual Air that goes into the tank?

If its the former, I'd be being cheated as I'm Paying for a 120 fill and not getting a Fill; if its the Later then it doesnt matter in the slightest...

Another question is Why dont they fill it all the way? are there diving or other safety concerns? I mean either the tank is rated to contain a certain psi or its not, why cheat yourself outta extra dive time?

 

[texasaubiefan]

Here's a link to an excellent article on dive tanks. As with everything in scuba, it ultimately depends on what you want to do and the type of diving you're going to do.

Dive Rite Express -- How to Select a SCUBA Tank

 

[Bobyjimmie]

Pvt Stash, from my experience on boats they fill to 3000 no matter if your tank is a 3000, hp or lp. One reason I believe is just because the guy filling doesnt look at each tank he just does it, so if your on a HP your gonna get shorted. The dive shop reason is those compressors cost a god awful fortune to be rated to give suitable gas for person consumption (oil free) and some of the compressors just dont have the ability to pump the HPs up to full capacity. HP tanks are nice because they are smaller versions of the tank you were gonna get but if your only getting 3000psi in a HP120, you basically got a smaller tank for that dive, correct me if I am wrong here guys but thats how I understand it so far.

 

[Buoyant1]

I tried 120's all last season, and they were a bit LONG for me and I went bottom heavy...but this year I switched to 119's and they were perfect so I bought two...It's all about where you dive, what kinds of dives etc...it may cost more to fill the larger tank, but will you NEED all of that breathing gas? I ddon't know of any shops that "pro-rate" fills based upon what's left in the tank. If I have 700psi left or 2100 psi left, I still get charged the same price.

 

[NEWIN50]

You have probably decided by now what you will buy, but I would suggest you try renting a 100 and a 120 a few times - before you buy.

As new divers our air consumption is at its highest, granted this will improve with more dives, but if you are going on a boat or a deeper dive you don't want to be cutting your dive short of the allowed bottom time, and calling the dive early to maintain a safe reserve in your tank.

Coming back with extra air in your tank is never a problem, not having enough - before the dive ends is.

I bought 120's and enjoy the extra air reserve, but think 100's might have been just as good - lighter to lug around and can be doubled up if you decide to dive doubles in the future, without being a weight lifter.

Good luck with your decisions.

 

[gcbryan]

I'm a big guy, jus' under 6' 3", and was thinking that when I get My tanks I'd go with the 120's , but this comment about 120's being shortchanged on air fills rankles me a bit... or maybe it doesnt...

It all depends on how the fill is being Charged, when you get charged to fill your tank are you charged based on its size? (80, 100, 120) or are you charged for the amount of Actual Air that goes into the tank?

If its the former, I'd be being cheated as I'm Paying for a 120 fill and not getting a Fill; if its the Later then it doesnt matter in the slightest...

Another question is Why dont they fill it all the way? are there diving or other safety concerns? I mean either the tank is rated to contain a certain psi or its not, why cheat yourself outta extra dive time?

In general, you are being charged a set price for a fill. At most dive shops it's the same for any size single tank. The only real issue is cost of the tank and size/balance. A larger tank costs more so if you are a smaller person you may not need the extra gas. Otherwise, more is usually better. Some tanks are taller and narrower while others are shorter and wider. I'm 6'1" and I prefer the 119's. They trim out well for me.

Some dive shops and many boats can only fill to 3,000 (depends on their compressor) but in my area at least most shops can and do fill to 3,500. Even if you ocassionally get a 3,000 fill you still have more gas than with an 80 cu ft tank. To me there's no downside as long as you can afford it and it trims out well for your body.