Factor in all of the above (cost of rent vs air fill, visual costs, hydro costs).
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<DIV>Don't forget to factor in o2 cleaning costs if you do nitrox partial pressure filling.</DIV>
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<DIV>Then like
Reefhound said, factor in the cost of auto gas is $3/gallon to make that 2nd trip to return the tank.</DIV>
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But to me the real benefit of owning tanks is convience and having the tank you want (steel, certain size, etc).</DIV>
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Example: You want to go diving saturday morning. If you have to drive 30 minutes out of your way to pick up a rental tank and then 30 minutes back, you've spend at least $10 extra bucks in gas and taken up a minimum of an hour or more of your time. Then you have to do the same thing to get the tank returned in the allotted rental time. It's just a huge hassle.</DIV>
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<DIV>You still have to go in to get fills, but you can do it on your time and during the work week, etc. When it doesn't interfere with 'dive time'.</DIV>
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<DIV>The other advantage is that if you want a tank besides an AL80, it's harder to rent them. So if you want a steel HP100 or HP120 or a set of doubles, you really want your own tanks.</DIV>
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<DIV>The initial cost might be higher, but it sure is nice not having to go to the hassle of rental tanks.</DIV>
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