low pressure steel 125

[matt_unique]

What are differences I should be aware of between aluminum 80 or 100 vs low pressure steel 125? I have an opportunity to buy two of the low pressure tanks and they have never been used, but will need to be hydroed. I am trying to figure out all of the pros and cons, and I figured I could get some great insight. Thanks I look forward to reading the posts!

I used a lp steel 120 last year for several dives. The weight is just ridiculous compared to other tanks (even hp steel 120) and they are wider. My BC strap could barely get around this tank. I used it and in the water you will not notice very much but dealing with these on the surface is too much hassle in my opinion.

--Matt

 

[DEEPLOU]

Originally Posted by skistowe
What are differences I should be aware of between aluminum 80 or 100 vs low pressure steel 125? I have an opportunity to buy two of the low pressure tanks and they have never been used, but will need to be hydroed. I am trying to figure out all of the pros and cons, and I figured I could get some great insight. Thanks I look forward to reading the posts!

I got a pair of 112s, figuring I would double them at some point. Since I only use them as singles, a couple of 125s would have been a better choice.

I did the 112's and did double them up, doubling the 125's would definately be out of the question.

They are a real pain to change out between dives on a pitching boat.

That's one of the reasons I went over to doubles. When the dive plan does call for switching over to another set, doubles are much easier to change than a single w/pony.


As previously stated if pumped (to 3500) you can get 165 cuft in them, even at 3000 you have 142 cuft.
So if your tall enough and strong enough to handle them .....
Its your choice

 

[D1v1n]

I can get the tanks at $150 for two or $100 for one, they need to be hydroed and they need valves, either k or something else. With the valves I am lost as to which one to go with. What do you think? I appreciate your insight and comments.

Well you will probably end up getting several different tanks before you're done.
I personally don't care for aluminum...but that's just my choice because of the extra weight required on your belt and some might not be safe if they fall under certain numbers and dates.
The 125 might as well be considered a water heater but if the price was right I'd consider it...heck even jump at the chance if priced right.
I am very partial to steel tanks myself.

edited to add; could you swim up the 125 if you had a BC failure?
I won't dive double steels wet just for that reason.

Andy

 

[sharky001]

I have two OMS LP 125s - and they're sweeeeet to dive with. That said, and it's been mentioned above they are an absolute b^&%h on land because they're just under 60 lbs (ea.) full and a fairly tall cylinder (the height of the cylinder means that you have to be tall to carry them or use two hands - b/c the distance between the valve and the boot is too great). I believe the OMS (Faber) 125 is -9 full and neutral when empty. They're a pleasure underwater and don't cause buoyancy issues. Unfortunately, I have one on the west coast and one on the east coast (though - great when I travel back and forth) so, when I do multiple dives, I use a Al 80 - what an insane difference. Steel cylinders with a decent BC setup feel so dang good underwater.

Just make sure you're strong enough to throw these bad-boys around - they're big! For boat diving they're great ... for shore diving with difficult entries, they're very difficult...

 

[D1v1n]

What would be the advantages of the H valve? I normally just have a k valve on my existing tanks. Is the H valve a din connection? I believe that my first stage has a yoke connection. What is your take on it.....Currently I have a MK25 first stage, and it sounds like I would have to convert it to din...or do you have to buy a new first stage...

they're a ***** on land but dive well. you can jam 160 cuft into them (spare me the flames...). If it gets too cumbersome, you can banish it to O2 service, get a transfill whip and pp blend your own trox (providing you can find a shop that will top-off)
if the price is right....
ps. get an H-valve

 

[msandler]

Since this tank will hold the equivalent of a common set of doubles, you can achieve acceptable redundancy with an H-valve (neophytes spare me the lecture). A deep wreck dive is a good example for this application. In my experience, most tech charters acknowledge this config. They are some advantages to a single (with two regs) over a a set of doubles; easy to manage, less weight in water to compensate, less drag... While your buddy is diving double 85s you can dive your single. For the most versatility, get a 200 bar H with a plug (so you can use it as a single K-type valve) and yoke inserts (hence the 200bar). 2 regs, 1 reg, yoke, 200 and 300 bar compatibility. Yes you can put a 300 bar DIN reg in a 200 bar DIN valve (a few threads will show but its still better than yoke due to the captured O-ring).

If I can get the same deal, send me a PM - thanks

 

[Sideband]

When you're figuring out the weight belt stuff, look at the empty tank buoyancy. My 125's weigh are exactly 1 billion pounds negative at the start of the dive, but neutral at the end. AL 80's are +4.4.

LOL

My new favorite tanks though are the LP 85's I just snarfed up. They're lighter than an aluminum 80 but hold 129 cubic feet when they're fully loaded.

This one you are going to have to explain to me. How do you get 44 *EXTRA* CF of air into an 85 cf tank? Thats half again as much as it is designed for. I've heard of cave fills, but wow. Even if you have them as doubles that seems like a lot. What am I missing?

Joe

 

[Sideband]

I can get the tanks at $150 for two or $100 for one, they need to be hydroed and they need valves, either k or something else. With the valves I am lost as to which one to go with. What do you think? I appreciate your insight and comments.

I would have already paid the man for both. I bought my LP95 for $185 this year and thought I had a good deal. Heck, AL80's go for just a bit over $100 each new. Even if you hated them you could probably get double what you paid for them, or more, on Ebay.

Joe

 

[Soggy]

LOL

This one you are going to have to explain to me. How do you get 44 *EXTRA* CF of air into an 85 cf tank? Thats half again as much as it is designed for. I've heard of cave fills, but wow. Even if you have them as doubles that seems like a lot. What am I missing?

Joe

Probably pumping them to 4000 psi, which isn't uncommon in Florida or Europe.
85cft/2640psi * 4000psi = 129 cft.

 

[Sideband]

Probably pumping them to 4000 psi, which isn't uncommon in Florida or Europe.
85cft/2640psi * 4000psi = 129 cft.

At what point does the burst disk come into play? Do they change out the valve to a HP valve for that? I thought the threads were different on the neck. Sorry. Don't mean to hijack here but this just seems extreme to me. I guess I can stop feeling like I'm doing something wrong when I get a fill to almost 3000psi in my LP95 eh?

Joe