Key Largo fast VIP's and fills?

Hi,
I'll be down there soon and wonder if it's possible to get tanks VIP fast anywhere; say drop off before 6pm and get back the next morning ? It would be real convenient if I could pick up clean tanks after checking out of hotel in the morning; anyplace offer this kind of speed in Key Largo? It would be nice to get this done while I'm there even though they still have a month before the VIP year is up. Also, where is good to get fast air/nitrox fills for HP steel tanks while you wait close to MM100? Would need to get fills probably within the 45 minutes between a.m and p.m trips.

Is it OK to fill a tank with air and the next time it is filled - to be filled with say banked 32% NITROX? I usually dive with just air, but sometimes would prefer nitrox for the dive plan. My tanks were oxygen cleaned last vip and the way I understand nitrox mixing, sometimes pure oxygen is added into the tank with the right amount of compressed air to get the proper %. So does using air (21%) to fill your tanks somehow make them unclean for nitrox use? It seems to me that switching between air(21%) and higher oxygen mixes(up to 40%) should not be a problem. Is it normal for a LDS to drain tanks of air and then fill with the banked nitrox mix, or to calculate existing psi for volume of air and add oxygen and air to create the desired %? I know that there are several gas mixing methods; is there a LDS in Key Largo that could serve my needs by giving me air fills into my tanks when I want them and then switch to 32%nitrox when I need them quickly? Or would it be faster fills to find a shop that could put 32% into my tanks that have air in them now and then just stick with 32% for all dives? What shop could do this that is open the latest in the evening; not sure what time I'll be arriving, but have dives planned the next morning after arriving.I have read some posts about shops being quite strict with fills, so just trying to get some info before I show up for some diving; I don't want to put the nitrox band stickers on my steel tanks but I do have the nitrox card.
Thanks,
Matt

I dont claim to be a expert as im still a little green at this but indeed its possible to Get a Vip done that quick you need to talk to the shops in that area and make arrangments ahead of time to have it done though there may be a special fee for keeping some one there late. If you just walk in off the street and ask for a vip by tomorrow its comes across as pushy and alot of shops will tell you NO. Also how many tanks are you talking about 2 shouldnt be a problem but 10 would be hard to do.

As far as your question on if sticking air into a tank ruins its O2 clean all i can say is welcome to a huge debate. You have grade E air & Modified Grade E air then there is electrical compressors and gas etc etc. Rather than get into it ill just defer to others to answer. Keep in mind this is a technical diving thread so they may be talking about spec higher than recreational diving.

http://www.scubaboard.com/forums/te...lties/28401-grade-e-modified-grade-e-air.html

To answer your latter ? most places will not blow off all the air in your tank they will just analyze your mix plug it into a calculator and blend with it. Say you have 21% in your tank and you want 32% ill take the PSI in your tank then add 36% to blank PSI then add 21% again to top you off then analyze you and you should come out at 32%. Mind you I use a custom program that lets me just plug in the variables and spits out a filling schedual.

FAST FILLING IS DANGEROUS. It shortens the life of your tank it can get the fill tech and you hurt. Also you actually get less gass due to heat expansion. Find a shop that will Rent tanks in the size you like. spend the $ for one set use your set rent theres return theres use yours. Tell them your window they should work with you on it. Till bug season starts they shouldnt be that busy.

To avoid all of the o2 cleaning stuff use a shop with banked mix if they bank mix and you use up most of your air on your dives then your going to have a easy time switching mixes as a few 100 psi will not mess up the % so much that they cant just put your tank on the whip and change your mix by turning a few valves. 3300 psi air tank with 100psi in it toped with 36% will give you 35.5% mix easly with in limits of use for standard dive charts.

just noticed this thread

http://www.scubaboard.com/forums/basic-scuba-discussions/344838-e-grade-air-over-pure-o2-2.html

Getting the VIP should be relatively easy (there may be an issue related to a quick O2 clean approval, especially as officially they should at least be cleaning your valves). Call Conch Republic and check with Brenda. Quiescence is closer to MM100 and they are actually the local hydro location, but getting your tanks done overnight may not be possible (especially on the weekend).

I think you are going to be running into trouble with getting good fills between your dives unless you check with the op you are diving with. Quiescence, Conch Republic and Ocean Divers bank gas, but getting your tanks to them, getting them filled (and of course filling tanks for their divers will come first) and getting back quickly is going to be a challenge. They will top off with their bank gas (30/32/36 depending on the shop), unless you ask for a specific mix which will certainly take more time. Most shops in the Keys are pretty picky about switching between Air and Voodoo gas - not a big issue for shops that bank mix, but these guys run conservatively. You could just use your tanks for nitrox for the deeper dives and rent air tanks (most ops include this in the price anyway).