Ean30?

[kelemvor]

I went diving this weekend, and needed a nitrox fill. The outfit I was diving with had nitrox, and so I dropped one of my tanks with them for a fill after a dive. When I asked for 36% they told me they only banked 30%. It wasn't a problem as I just used that tank last and was still well within limits for nitrogen loading.

Is it common for shops to bank only 30%? Particularly, is it common enough that I should be asking about this when planning a dive trip? The shops around the area where I live either do partial pressure blending or bank 36% from a membrane system.


Also, I'm curious - why would a shop choose to bank a mix like that instead of blending or banking a higher mix they could thin out if necessary?

 

[rhwestfall]

How does the MOD for 30% match up with the majority of the diving in that area? Seems that would be the reasoning.....

 

[DivemasterDennis]

In my experience, most common banked mixes are 32 and 36, but each location may/will differ. Just be sure to check your mix before every dive.
DivemasterDennis

 

[kelemvor]

How does the MOD for 30% match up with the majority of the diving in that area? Seems that would be the reasoning.....

The five sites I visited with them were selected by the captain, and the deepest was 87 feet (if you went off the reef plateau to see the side of the reef). From what I understand there is a ledge in the area that goes down to 100' if you hit the bottom of the ledge. This one would be a problem for EAN36. I brought 36 because when we planned the trip they said we wouldn't be doing that site.

Perhaps they have some deeper dives they do that require the leaner mix.

My dives with them were 87, 57, 41, 23, 23.

I bet rhwestfall is right, there must be some (many?) sites off islamorada that are deeper. This was a trip arranged by an LDS and there were plenty of beginners. The captain probably selected shallow sites deliberately.



Thanks for the input guys, I'll just have to put it on my pre trip checklist to call the operator and find out about available mixes. I've got four tanks, so I usually just bring them full and haven't until now had to get a fill on the go.

 

[iluvtheocean]

Which operator was it? I know Rainbow Reef banks 30% which is even stated on their website. most of the reefs they do top off @ 90 but they also do a lot of wrecks such as the Spiegel Grove and the Duane

 

[tomfcrist]

Quite a few shops I dive with only bank 28 and 30. They will pp blend custom mixes for you if requested though. It's usuall relative to the depths those boats usually dive.

 

[Steve_C]

Main shop I use banks 30% as do some other places I sometimes use. In NC lots of the dive sites are 100+. In fact the majority of the dive sites are 100+. I prefer to stay at 1.3 or below. May be overkill but on some dives I dive 28.

 

[kelemvor]

Which operator was it? I know Rainbow Reef banks 30% which is even stated on their website. most of the reefs they do top off @ 90 but they also do a lot of wrecks such as the Spiegel Grove and the Duane

Florida Keys Dive Center.

 

[jebsurf]

Main shop I use banks 30% as do some other places I sometimes use. In NC lots of the dive sites are 100+. In fact the majority of the dive sites are 100+. I prefer to stay at 1.3 or below. May be overkill but on some dives I dive 28.

Same here. I like to stay within 1.3

 

[kotik]

they only banked 30%. It wasn't a problem as I just used that tank last and was still well within limits for nitrogen loading.?

Remember when it comes to staying within NDL's, you generally get more bottom time by doing your deeper dives first. So if you had two dives planned to the same actual depth, it's probably a better strategy to use the leaner mix first, since that has the effect of making it a deeper dive in terms of equivalent nitrogen loading.