Hetland:
If I'm not mistaken, the LDS compressor is outdoors. Running that thing in 95 degree Mobile afternoons to direct fill tanks can NOT be helping the cooling system. As a result, I'm willing to bet that the maintenance costs will be somewhat higher than they should be. It seems that a much more efficient approach would be to run the compressor during the cooler hours in the morning or evening, just to top off the (mythical) air banks. A decent cascade system would maximize the number of potential fills that could be obtained during periods of high customer demand. A blending stick would reduce the labor currently being used for partial pressure blending of the banks. I'm sure that the gas *could* be produced for much less than it currently is. . . . there's just no motivation for doing so.
Other than that, I pretty much agree with both of you guys.
When 99.9% of my diving was shore based, I didn't think twice about splurging on some EAN for a special trip out into the gulf. I might dive 6 or 8 tanks of Nitrox in a year. I might have save $50 or so a year by driving to PCB for gas fills. Obviously, it wasn't worth the hassle.
Now that a much larger percentage of my diving is in the 60'-120' range, the numbers paint a different picture. When I realized that it can cost me $55 more each week to fill all my tanks at shop "A" vs. shop "B". . . I quickly determined that I was talking about a best-case cost difference of $220 each month, or $2,800.00 annually. For me, that amount of money significantly impacts my ability to dive as frequently as I'd like.
Of course Pat's place is a 6 hour round trip, so It's not exactly feasible for me to swing by after work! What is feasible for me, however, is this: I never refill tanks in Mobile unless I know that I need them for a certain trip in the next couple of days. I just leave them in my garage. If I have an opportunity to head to PCB (or Marianna) I just take the empties along for the ride, and fill them up while I'm in town. Panama City Dive Charters' fill system consistently gives me solid, room temperature 3,442psi fills at 32% (+/- a couple of tenths), and it does it in about 30 minutes. Filling my tanks like this has also stopped me from repeating a rather painful mistake I've made in the past: dumping full tanks of air because I suddenly found out that I needed EAN in them for the next day. Conversely, I haven't 'had' to waste Nitrox at a shallow shore site in a long time, either.
In my opinion, the statement: "Nitrox isn't a large portion of our gas sales, therefore we don't see the need to invest in an efficient system" is essentially a self-fulfilling prophecy. I'd be up there getting several fills each week if it was cost effective for me to do so. It isn't, so I'm not. There are people in Mobile that have their own compressors and blend their own Nitrox for this reason. There are also at least a few that I know of in the Pensacola area that do the same. For someone living in PCB, I can't imagine even consider going with a private system. . . not with Pat's capacity and prices. I'll happily give Pat all my gas money. . any time I'm nearby!
Carl