Question PST 104 characteristics with lean trimix

[tbone1004]

Yeah, so here is the problem: I have no experience with PST 104 in any configuration. I know the specs but would like to hear real-life experience before I spend a small fortune on gas fills. Backmount crowd raves about these tanks though...

Basically just dive with air/EAN32 and pay attention when the tanks are breathed down and you'll know what they breathe like. Amigos may have a set of 104 sidemount bottles to rent.

30/30 starts at 2500psi
18/45, starts at 2000psi
12/70 starts at 1000psi

Basically they stay heavy through the whole dive, especially newer ones. They are not bottles I love for sidemount and much prefer Faber LP121's for trimix. If you're diving Faber 85's now then the Faber 108's will dive effectively the same as your 85's and you can just do the experiment above with your own 85's. PST's are inherently heavier and you'll need to remove about 6lbs of lead to compensate for that. If you stay with Faber then no change needed as their empty buoyancy characteristics are effectively the same.

 

[J-Vo]

@mr_v Faber 108s CCR side mount with TRIMIX are glorious. Probably easier to get your hands on and may be cheaper as well.

Caveat: I don't need a lot of lead. With NX in LP85s I'm way overweighted, even with my Halo undergarment.

 

[mr_v]

@mr_v Faber 108s CCR side mount with TRIMIX are glorious. Probably easier to get your hands on and may be cheaper as well.

Caveat: I don't need a lot of lead. With NX in LP85s I'm way overweighted, even with my Halo undergarment.

Same here. In Cave Country I am always diving with Arctic undergarments and can still use more padding.

I'll try LP108s, too. Size is a bit of a concern, but these tanks will typically be reserved for deep, long cave dives where I don't plan to squeeze into too many tight places. I did some numbers and LP108s come up quite nicely given the AL72 bailouts that I already have.

 

[rjack321]

Yeah, so here is the problem: I have no experience with PST 104 in any configuration. I know the specs but would like to hear real-life experience before I spend a small fortune on gas fills. Backmount crowd raves about these tanks though...

If you own the tanks and want to "try them" just fill them e.g 1600psi full with EAN32%. That simulates 15/55 gas pretty well. Consider the helium fraction as weightless and you're going to be close tank trim wise.

I don't have 104s but I have used both 108s and now 130s SM with 15/55 and I love them both with high helium mixes.

 

[mr_v]

If you own the tanks and want to "try them" just fill them e.g 1600psi full with EAN32%. That simulates 15/55 gas pretty well. Consider the helium fraction as weightless and you're going to be close tank trim wise.

I don't have 104s but I have used both 108s and now 130s SM with 15/55 and I love them both with high helium mixes.

I went with Worthington LP85s. Even with 10/70 they're not feathers, but they trim exceptionally well. If I need more bailout, I'll drop stages + get a backup scoot.

 

[rjack321]

I went with Worthington LP85s. Even with 10/70 they're not feathers, but they trim exceptionally well. If I need more bailout, I'll drop stages + get a backup scoot.

Yeah I'm not a fan of "just" bringing stages if I can help it. You end up with less gas on you and your total volume is scattered around in little nuggets which aren't immediately accessible. I am more of a RB80 like BO person when possible - put the largest tanks you can on your person and only then start to add stages.

 

[mr_v]

Yeah I'm not a fan of "just" bringing stages if I can help it. You end up with less gas on you and your total volume is scattered around in little nuggets which aren't immediately accessible. I am more of a RB80 like BO person when possible - put the largest tanks you can on your person and only then start to add stages.

I thought about it and pulled the trigger on Worthy LP85s because they'll get me where I need to go now and later I'll upgrade to larger tanks while these will become a part of my OC fleet.

 

[tbone1004]

I went with Worthington LP85s. Even with 10/70 they're not feathers, but they trim exceptionally well. If I need more bailout, I'll drop stages + get a backup scoot.

Same here. In Cave Country I am always diving with Arctic undergarments and can still use more padding.

I'll try LP108s, too. Size is a bit of a concern, but these tanks will typically be reserved for deep, long cave dives where I don't plan to squeeze into too many tight places. I did some numbers and LP108s come up quite nicely given the AL72 bailouts that I already have.

Worthington LP85's handle about the same as PST LP104's, heavy! Very different than Faber 85's.

I'm not sure how tight of places you're going into, but my primary tanks are LP121's and there are exceedingly few places that they become an issue of whether I can fit or not. It's never tight, it's always twist where the length becomes an issue as the two of them together are still smaller than my shoulders.

 

[mr_v]

Worthington LP85's handle about the same as PST LP104's, heavy! Very different than Faber 85's.

I'm not sure how tight of places you're going into, but my primary tanks are LP121's and there are exceedingly few places that they become an issue of whether I can fit or not. It's never tight, it's always twist where the length becomes an issue as the two of them together are still smaller than my shoulders.

OC sidemount - it gets tight.

CC - not that tight - Meg kinda gets in the way; I see a Gemini in my future.

Tom, judging by your posts you're a lot taller and bigger than I am, so the length may be an issue for me, but I am open to larger tanks in the future. I may also try Faber 85 for the sake of the weight, but I do love how Worthys stay close and parallel to the body.