High Pressure vs. low pressure

[david_57]

Yeh I have double HP 100's Galvanise never any problems with fills and I was able to drop 8 lbs of my belt

[fisheater]

I don't have a problem with short fills on my Faber HP120.

I drop off my tank at the LDS on my way to lunch and pick it up after lunch. They know to fill it, let it cool and then top it off. I give them plenty of time to do it right and they always do.

If I'm diving where I need to get a fill during a SI, I get the fill done right away and let them know that I can wait a bit for the tank to cool.

[skdvr]

Originally Posted by Rainer

Pretty good track record? Or do you mean perfect?

I dont know that I would say perfect. For one I am sure that they shorten life of the tank. Yes you are saving money buying them over the HP version so if you do not mind replacing them sooner that is fine with me. Obviously it depends on how much you are diving and how often they are being Cave Filled. I am also fairly certain (Not positive) that most of the catastrophic failers have happend in Fl and with pumped tanks. I have heard (or read) others talking about this same issue, so there is not much point to a discussion becuase if you think that pumping tanks is what you want to do then go for it. I for one will not do that...

Phil

[Rainer]

Please cite ONE catastrophic failure of an LP over-filled. ONE. And all the people I know over-filling (between 3000-3600) have had zero problems with hydros. This does assume that once filled, you actually go out and immediately dive the cylinders (i.e. you aren't keeping them pumped up like that for weeks). If my cylinders are going to wait, they only see 3000psi. Sorry, but your "fears" just aren't based on facts (or experience). Your "I heard it from a friend's neighbor's roommate's cousin" doesn't cut it. Try talking to some cavers.

[cmburch]

I like the HP100. It is a very nice easy to use size. The new tanks come with a valve for Yoke or DIN. Buoyancy empty is about the same for both tanks, but the LP95 is considerably heavier. The extra weight may make a difference if there is a long walk or hike involved in getting to the water. As for fills, it does not make sense to overfill an LP tank when an HP tank can be used instead. Here is a link for different fill pressures for the HP tank.

Worthington X-Series SCUBA Diving Tanks

Look also at the HP120 and compare the size and weight to the LP95. If I think about comparing tanks, I look at cylinder weight and buoyancy empty first for comparison because I do a lot of hiking. Then I look at capacity - the HP tanks have the LP beat from above link. Then I look at length of the cylinder. The HP100 for me is the ideal SCUBA Tank. I use HP130s when I don't have far to walk.

[Rainer]

Originally Posted by cmburch

As for fills, it does not make sense to overfill an LP tank when an HP tank can be used instead.

Why? LP costs a lot less. Awhile ago (last year) you could find LP85s (basically the same size as HP100s) for $150 less than the HP100. If you get your 85s mildly over-filled to 3000psi then what have you saved by getting the HP cylinder? Answer, nothing. This of course assumes you can get slight over-fills.

There are also PLENTY of reasons why some people prefer LPs. Transfilling and PP blending are two such reasons. If you don't care about them, then HP might be for you.

Again, I have a mix of both (mostly HP actually).

Originally Posted by cmburch

The HP100 for me is the ideal SCUBA Tank.

It's a very good sized cylinder, I agree. What's right for you, though, might not be ideal for others. I'd suggest people first determine how much capacity they require, then have much weight, then what they hope to do with the cylinder. Hopefully those answers will help guide their search for their own ideal cylinder.

[Rainer]

LOL. I guess that's what you get when you only rely on the online medium to do your SCUBA learning. Too funny cburb.

[caroln]

I love doubled LP 85's. HP 100's are nice for singles, but for me as doubles, I'm extremely head heavy. With the 85's, I'm perfectly balanced. That's what I rent in FL, so I like to dive them at home so I'm super familiar with my cave setup. Cranked up to 3600 they have a ton of gas. Even at 3000, they have a very respectable amount of gas.

[Jack Hammer]

Originally Posted by Rainer

Um, sort of depends on what pressure you intend to overfill to, doesn't it? I usually push my LPs to 3000, but sometimes to 3600. The question should simply be to what pressure can you overfill (and what pressure do you want). For me, it's all about capacity, not pressure.

Excellent point Rainer, as was the other about the cost of LP v HP tanks. I'm just trying to make the OP aware that they should be looking at more than just the cf capacity of a tank.

Anytime someone wants to buy a tank, especially if its their first tank, they need to look at many aspects of the tanks considered. I think the first should be the intended use of the tank vs how it'll likely actually be used. Then lots of other factors come in, such as the cf capacity, the physical dimensions & weight, HP v LP, cost, tanks buoancy haracteristics, availability of fills, ability to grow with it, physical size of diver, air comsumption rate, etc, etc

Jack

[Rainer]

Nice post, Jack.