Tank size & nitrox HELP

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11kiwidiver

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Havent been in the water for about 2 years.. just moved to south florida so im ready to start diving again :D Currently settin up my rig and Im having trouble with tank selection and the practical nature of nitrox..

1. I have a nitrox cert and have done most of my dives (less than 30) breathing it... I want a nitrox tank.. but if I do multiple tank dives most boats wont fill nitrox (?)... do you have an extra air tank, or do you usually rent (when EANx isnt available)

2. Im having trouble deciding on tank size.. Im not sure of my SAC rate because I havent dove with computers and as a result I dont know my "my average depth" (my new comp is in the mail :ar15:). Im sort of small (125lbs 5'9") and I have a pretty decent lung capacity (6L) because I play brass instruments. Looking at my past dives I sucked through AL80's pretty quickly (usually ending up with 600psi) so I think I should go for a bigger tank (for possibly doing air deco dives when I get the training). Would a 133cf 26in 40# some odd tank be too much for my size and current diving (NDL), also I would be wearing a 30# wing with a 3/2 wetsuit(so maybe this would be too much tank)




thanks
steve
 
Unless the boat has Nitrox or "safe air" (O2 compatible), they're not filling my O2 cleaned tanks. I'll just rent.

Second, you need to think about your wing selection. If is probably too big for your type of diving. Over in the BCs forum, there is a 'sticky' spreadsheet that deals with this stuff. Or call Tobin at Deep Sea Supply. He has this stuff down to an art form.

Physically, an HP 100 is an inch or so shorter than an Al80 and weights a couple of pounds more. If is considerably more negative. However, you are probably wearing 10# or so with that wetsuit so losing 6# for the tank change is no big deal. Adding a SS backplate (5#) to the mix might result in your not having any ditchable weight and that is bad (in my view). Try to have a few pounds of ditchable weight.

The HP 100 is a pretty practical tank. It isn't terribly heavy, it isn't terribly negative and it holds a lot of air. It is expensive when compared to aluminum tanks.

Richard
 
I think you may just need to dive more and learn to relax underwater. If you are only 125 pounds and 5 foot 9 inches and are burning through AL 80's on basic recreational dives then a bigger tank may not be your first priority. Especially if you are in shape and play instruments. Just slow down a bit, relax, breathe easy, take a refresher or more education, get more dives in, and rent tanks for a while. Then come back and re-evaluate all this stuff in a few more months. It's hard to know what to get when you don't know what you need yet.

I am 5 foot 9 inches and weigh 180 pounds and frequently return to the boat with over 1500 psi left in an Al 80 after an hour. This took a few hundred dives.

I personally find an HP 100 to be OVER KILL and too heavy for me in warm waters. With a BP/W and a HP 100 I am over weighted severely in warm water and I weigh more than you do.
 
dont worry about it if its under 40%... dont most places fill it with 100% 02 first and then blend it to the correct EANx?
 
NO, my experience in Florida is Membranes on boats and Banks at Shops. Home blenders might or a small shop, it is almost impossible to get more than a couple hundred pounds into a SCUBA tank from a O2 bottle.
 
scubadoooo how much lift does your bp have.. and what wetsuit do you dive

I have a Dive Rite 30# wing with a 6 pound steel plate. I usually dive a full 3 mil with a 5 mil hood in Florida/warm salt water.

I own a HP100 tank and I love it when I am using my dry suit and want or need to take some weight off my belt up here in colder waters. In warm water with my steel plate, I only need two more pounds for a total of 8 pounds when I use an AL80. If I switch to the HP 100 then I am sinking like a rock and have to compensate with my BC. I prefer to dive a balanced rig and for me, an AL 80 is best in warm waters.

Like nitrox, tanks are only a tool. Decide what tool is best for your job. I hink more experience in your new environment will help you decide better. BTW, congrats on your move to warmer waters!
 
dont worry about it if its under 40%... dont most places fill it with 100% 02 first and then blend it to the correct EANx?

It all depends on the shop....my local dive shops all partial pressure blend (fill with O2 first, then top with air), but the bigger ones in "cave country" Florida all bank 32%.
 
https://www.shearwater.com/products/teric/

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