Mares 15 liter, 200 bar steel tank

[Ari]

During my searches for a scuba tank, I came upon an almost new (2 dives only, as per the owner) Mares 15 liter, 200 bar steel tank.

The owner asks 170$ for it, when in the shop it goes for about 370$. I tried to find more info about the tank and went to www.mares.com/en/erogatori/airtanks_en.html but still have some unanswered questions:

1. Who makes these tanks for Mares?
2. Is 200 bar considered high or low pressure? the conversion will get you to 2,900 psi, which is neither hp nor lp.
3. What are the buoyancy characteristics of the tank?
4. Does anyone have any experience with the Mares tanks and can make some kind of recommendation?

Any assistance will be appreciated.

Ari

 

[Diversauras]

Boker Tov,

To give a couple of quick answers to your questions,

I don't know who makes the tanks but it is down to two or three companies now. The difference is the make up of the steel, but new it shouldn't matter either way.

200 bar is LP

Buoyancy, negative at the end of the dive, 1.6Kilos or so, more negative at the start of the dive, 3Kilos or so, take it off your weight belt. I dive one with out a belt.

I had one I bought a techni sub 15l tank from Marina Divers years ago and loved it. At that price all I can say is buy it

 

[Ari]

I think I will. It looks like a good price for a good tank. But still, isn't lp rating up to 2,400-2,640 psi?

Ari

 

[devjr]

Ari, these European tanks are not high pressure only in the sense that they do not require the DIN connector under current industry practice. The 200 bar tank has been a common production item in Europe for decades. Similar tanks were in use over there when the US standard cylinder was rated 2250 psi. So, at one time, the 200 bar tank was certainly regarded as "high pressure". We didn't catch up until the mid 1970's when PST offered their 3000+ psi steel cylinder, now obsolescent. Also, simultaneously, 3000 psi aluminum cylinders entered production by various companies.

I advise you not to buy the Mares tank. The cylinders are not galvanized but are painted with a heavy urethane more suitable for fresh water. I assume that is in short supply in the Mideast.

 

[Ari]

Just the kind of info I was looking for.

You are right. We do have a shortage of fresh water. Salt water on the other hand is a different story.

What kind of protection would you suggest?

Ari

 

[devjr]

At the very beginning of SCUBA in the US, the company PST made an investment in producing hot dipped galvanized cylinders. Nothing superior to this has entered commercial markets. A close second is the metallized zinc coating used by Faber and Asahi. The Italian Faber tank has the added advantage of an INTERIOR coating.

Currently, PST do not have such an interior coating. In the past, they produced tanks with epoxy coatings but this turned out to be a big fiasco when rust penetrated the coatings and could not be tumbled out. The tanks had to be scrapped. Their conclusion was that a plain, sandblasted interior was the most practical. Faber, however, uses an oxide coating which, although it doesn't prevent all rust, it strongly resists the ordinary "powder coat" of rust resulting from some compressors. However, the compressed air supply is much improved since 20 years ago and this is less of a problem with all steel cylinders.

I like the HP tanks made by PST. Technologically, these are most impressive being very light in weight with very high pressure and capacity ratings. However, the LP tanks made by both Faber and PST are probably more useful to a "tech" diver as explained by Pug and others. These tanks are very strongly constructed and are often intentionally filled in excess of rated pressure, but I am not endorsing it to others for this reason in particular.

Good luck.