Should I buy a tank, or wait? If buy, What would be my best option?

[scubadada]

So, you save about $5 per cylinder when you own vs. rent (rental of a nitrox AL80, $15, minus the cost of a fill, $10). You still have to take your cylinders in for a fill and pick them up for use. You also have to do the yearly visual inspection and every 5-year hydro. If you are going to do 4 dives a day for the two days of a weekend, the logistics might not be so easy, maybe even more difficult if you'll be diving from different, distant marinas. Perhaps if you had 8 cylinders?

I'm frequently a visitor to Florida and often do 20 dives in a week, if I'm able. So, for $100 in cylinder costs, I don't have to fill my tanks and pick them up and don't have to maintain the cylinders. I often end up diving from 3 different marinas, separated by up to 30 miles.

Sometimes, the math can be difficult

 

[Damselfish]

I just got open water cert but already have scheduled AOW, Nitrox and plan on being quite an active diver. I am even considering a career change to the diving world. Im hooked. Im in Florida a few times a year to visit family and that is where I got my OW and will be getting AOW, Nitrox, but I live on Long Island New York. After I get my AOW this month I want to look into diving the northeast. Ny, Nj, Maine, and NC.

You might want to do AOW at home on LI or somewhere in the northeast, if you plan on diving here. Take the opportunity to get some training/mentorship in cold water. Getting certified in cold water then heading to warm is easy, the other direction is a bit more challenging.

And do lots of research on diving as a career so you know what you are actually getting into.

 

[CT-Rich]

I have four tanks. Two 120s & two AL 80s, all bought used. I fill them and store them full after a dive, when it is convenient. with rental tanks, you have to build pick up and drop off into your plans For the weekend. If you buy them and want to do nitrox, you will probably want to dedicate them as nitrox or air. If I want nitrox for a particular dive I will rent them because my tank diving is normally air.

Being able to wait until mid week to drop them off/ pick up mean I usually can dive because the opportunity presented itself, minimum extra trips required.

 

[RobCom]

Yes, but I am going to assume that your response indicates that as a new diver you don't understand the difference between PSI and volume. A cylinder has the advertised volume of air in it only when it is filled to its rated capacity. Fill it to different pressures and you get different volumes. To give you an illustration, let's see what happens if I fill 4 different cylinders to 3,000 PSI.

1. An AL 80 filled to 3,000 PSI will have about 77 cubic feet in it. (We think of it as 80, but it is less.)
2. An HP 100 filled to 3,000 PSI will have roughly 80 cubic feet in it.
3. An LP 85 filled to 3,000 wil have roughly 100 cubic feet in it.
4. An LP 108 filled to 3,000 will have roughly 120 cubic feet in it.

Why would someone want LP tanks? Just wondering what the point is if you can fill HP tanks to lower pressures. Are they cheaper or is there a technical reason for them?

 

[edwants2dive]

I seem to be running a half-way house for scuba tanks.
Started out hosting 2 AL 80s then 3 more moved in. 2 of them moved out giving their room to a steel HP 100 who then invited 2 steel HP 100 buddies to stay. Word got out and these 2 steel LP108s showed up at the door and I must say we have become the best of friends. Well things got quiet for a while and I hoped that I could relax. Low and behold these 2 crazy LP120s showed up and started causing all kind of hell. The house was just a crazy place. So I finally decided to put my foot down and make the bad apples find somewhere else to live so I could invite the kind of residents that would be a welcome addition long term. The 3 remaining AL80s and 2 LP120s found a new home making room for 2 more LP108s and a very nice couple who happen to be LP85s. Now that the dust has finally settled I think the last 2 HP100s are looking for another home where they will be better apricated. When they do I will wish them well. Hoping that is soon so the little one (AL40) will sleep through the night.

Just to add to the mix see my post from another thread above. I jumped into the own your own tank game early took me awhile to get it tweaked correctly. That said I like owning as opposed to renting for a few reasons all of which have been covered by other posters.

 

[Marie13]

Why would someone want LP tanks? Just wondering what the point is if you can fill HP tanks to lower pressures. Are they cheaper or is there a technical reason for them?

LP85 trim out nicely sidemount and are sort of the ideal for cave diving. You can overfill them beyond service pressure (depending on your dive shop if you’re not in cave country). They’re so nice I have them in the Midwest and getting slight overfills can be a PITA. I forgot who said it here but for SM cave dive diving their buoyancy characteristics are spot on.

I’m a tank hoarder. Now have 4 pairs of 85s. Two for Trimix and two for nitrox. Two pairs of LP50s, two AL40s and two AL80s (for deco and stage bottles).

 

[edwants2dive]

Why would someone want LP tanks? Just wondering what the point is if you can fill HP tanks to lower pressures. Are they cheaper or is there a technical reason for them?

An LP is easy to get overfilled and HP is hard to get filled to rated pressure in some places.
Remember the gas volume is at working pressure. HP100 working pressure is 3442 PSI LP108 working pressure is 2640 (2400 +10%). Both the LP108s and HP100s I own have very similar buoyancy characteristics but I get more gas in 108 especially when it is fill to 3000 PSI if my HP100 was at 3000 PSI I would have less gas.

 

[boulderjohn]

Why would someone want LP tanks? Just wondering what the point is if you can fill HP tanks to lower pressures. Are they cheaper or is there a technical reason for them?

A couple people posting after this explained it well. It can be hard to get a complete HP fill, and it is easy to get an LP fill and more. Let's say you have a HP 120 and it is filled to 3000 PSI, which is an underfill. You have about 100 cubic feet of gas. Let's say that instead you have an LP 108 and it is filled to 3000 PSI. You have about 120 cubic feet of gas.

 

[inquis]

This is one instance where the metric view shines. An HP120 (imperial) is a 14 liter (metric) tank, and an LP108 is a 17 liter tank. It's pretty obvious that when filled to the same pressure, the 17 l tank will hold more gas. (Of course, it's still an open question whether a shop WILL fill them to the same pressure.)

For equal metric volume (e.g., HP100 and LP85 are both 13 liters), the HP version will be a little heavier (both in and out of the water) and a little more expensive (currently running +$40 at DGX, though they were +$150 the last time I bought tanks new). Either might sway someone to pick the LP if filling wasn't an issue.

 

[pauldw]

Renting tanks usually isn't expensive, and if you're occasionally diving and are near a dive shop, that's something to think about. If you're shore diving far from a dive shop, having your own tank(s) is nice.

There is such a thing as hot dip galvanized steel tanks. Those tanks are supposed to be more corrosion resistant.

If you use nitrox, then you shouldn't fill your tanks with normal air since that'll cause problems with them being oxygen safe (although some places have clean enough air to do that). So the point about maybe having a dedicated air tank, and a dedicated nitrox tank, might make sense. (All three of my hot dip galvanized HP100's are nitrox.)

You do have to choose between using a tank valve with either DIN or yoke regs. DIN is better, yoke is more common, especially on dive trips (so if DIN, having a yoke adaptor is good for trips). But of course, already having regs makes that choice for you. And then, there's the fact that most tank valves have a spin out insert in the valve that allows the tank to be used with either DIN or yoke.

There are going to be a number of people on Scubaboard who ridicule this, but I like the valve knobs that have a red sleeve by the knob when closed, and a green one when opened (in this picture, the Vindicator is half way open):