Blending Nitrox From Nitrox (PSI & Bar)

[@lshstory]

Very helpful. Easy to understand. THX.

[@LakeHickoryScuba]

Glad you liked the video 이상화

[@ROB14ification]

It's like solving a soduko! Thanks for this series, very interesting and useful information made easy to comprehend. Greetings from Sweden.

[@LakeHickoryScuba]

You're welcome, glad you liked the series. And yes, I never though about it, but it does look like a Sudoku puzzle.

[@unclemilton815]

Mate, again thank you so much Bryan.

[@LakeHickoryScuba]

You're welcome Milton.

[@Will-ol9lp]

This is great to know. Keep them coming

[@LakeHickoryScuba]

Glad you enjoyed them.

[@coreybaldwin989]

Ok so do you still have to go through the tic tac toe board just to top of a tank? Or is that just to do the changing of the mixture?

[@LakeHickoryScuba]

Great question. In the event you had the same mixture in your cylinder that would be topping off with, then you would simply top it off with no calculation. But as you stated, if you wanted to change you mixture for the second dive, then yes, you would need to do the calculation.

[@kentmartin3746]

So once you figure out the 38% , you go back to the first step in 1st video to figure the mix of air to O2 to do the blending?

[@LakeHickoryScuba]

In short yes, and you can always fill from banked Nitrox if it is already blended, or simply do continuous flow mix through a Nitrox Stick to top it off as well.

[@adambonner3130]

Hi there great video's watch them all regarding this blending nitrox to nitrox im slightly confused ive used the system you use and ive come up with my figures but really looking for confirmation so I have a stage cylinder currently with 55% nitrox that is 58 bar of pressure wanting it back up at 200 bar with 60% nitrox can you walk me thru it cheers Adam bonner uk

[@LakeHickoryScuba]

Hello Adam, according to my math, you would need to add 142 bar of 62% to get the blend and fill you need. Here is the math broke down. Desired fill 200 bar at 60% (.60 * 200 bar = 120). Current mix 58 bar at 55% (.55 * 58 = 31.9). (200 - 58 = 142), (120 - 31.9 =88.1). Required fill (88.1 / 142 = .62).

[@adambonner3130]

@@LakeHickoryScuba thank you so much can i now put this by you see what your thoughts are ok I have again 58 bar in the stage cylinder with 45% nitrox I have a cylinder with 100% in that I want to decant from to to take the 45% nitrox up to 60% and finish with the stage cylinder at 200 bar thanks in advance

[@SeattleRingHunter]

Excellent content God bless you sir! 🤙 Cheers, #SeattleRingHunter

[@LakeHickoryScuba]

Thanks Seattle Ring Hunter.

[@johnb2271]

Nice job, Bryan

[@LakeHickoryScuba]

Thanks John

[@DecoLounge-scuba]

The question on my test says the tank is starting out empty... so if i put starting pressure at 0, (trying to get .36 with .40), it just comes out to .36. Starting f02 X 0 is zero, so i messed up somewhere

[@LakeHickoryScuba]

Hello @DecoLounge-scuba, if I am reading your question correctly, you have an empty cylinder (assuming an Aluminum 80) and you are wanting 36%, but you are starting with 40%. So you would uses the 40% and add 563 psi to the empty cylinder. You would then top the cylinder off with 2437 psi of standard 21%. This should give you the 36% you desire. Another great tool that you can use is the Multi Deco app. It has a built in Nitrox and Trimix mixer calculator. We use it all the time when filling cylinders. It prevents the need to drain a cylinder first when partial pressure blending. Hope this helps.

[@superbholidays3520]

👍👍

[@LakeHickoryScuba]

Glad you liked it.

[@landgin3781]

Helium is expensive. Take notes folks

[@LakeHickoryScuba]

Very Expensive

[@scubasteveandunderwaterroc3547]

If I remember right you can fix the cost issue by going ccr

[@rahuls5881]

But how does this help? now you need X bars of NX38. instead why not directly solve for how much AIR and how much pure O2 to add? g_c = current gas blend (Nitrox) (% of O2) g_f = final nitrox blend % of O2 b_c = current tabk pressure. b_f = final tank pressure so Solve g_f * b_f = g_c * b_c + 0.21 * X + 1.0 (g_f - g_c - X) for X thats how many bar of AIR must be added. and top rest with O2 finally until g_f bar achieved. direct. and simple math.

[@LakeHickoryScuba]

Great question Rahul S, depending on what compressor system a shop has, when it comes to the economic effect of running a compressor non stop or the cost of partial pressure blending, using remaining gas to mix is way cheaper and more cost effective.

[@rahuls5881]

@@LakeHickoryScuba my equations do assume remaining gas in the mix. so you have some blend of NX and then simply add air and O2 to reach target mix. thats it.

[@olivenzoarnolda5115]

Thank you, Sir, so I have to have a higher pressure O2 tank than 200 bar to top up at the end. If not, the gas will be equalised back into the O2 cylinder.

[@revtechmarine]

Now you're just showing off lol that's seriously not worth it just drain the cylinder and pretend the visual doesn't matter just kidding unless you're talking about $trimix$$ but that's fancy little hashtag you made is a lot easier than the long formula it PCI PSI gives you in there course

[@LakeHickoryScuba]

Of course is much easier to top off if you are using a Nitrox Stick. Glad you liked the fancy hashtag, took me forever to get it the size I wanted it, so it would show up on camera in a legible manner. LOL