View Full Version : tank malfunctions???

10-20-2007, 13:57
how about tank malfunctions....what can go wrong with a tank....the reason i ask is that when i do buy one i was thinking of going with a used one or something...but do things go wrong with tanks?? at the valves or something...i know they have to be hydrostatically tested every so often..but it seems to me its like a steel ball bearing...not much to mess up really....although i know some ppl that can break a steel ball bearing..LOL.....:smilie39:

10-20-2007, 14:04
They can rust or oxidize. Valves can leak, the outside can get dented. Basically anything that can happen to steel and AL can happen to a tank if it's not cared for.

ScubaToys Larry
10-20-2007, 14:06
There are a few things to watch for. Steel tanks can get water in them and that can cause corrosion, making you have to tumble it before it will pass a visual.

And aluminum tanks, make sure you don't get any 6351 aluminum tanks which virtually no places will want to fill. If you get a tank after mid 88 - in the 90's to be safe - then you should have no problems with that alloy.

And some very old tanks will have valves that either leak, or have unacceptable burst disks (blow straight out instead of in opposing directions).

So I've had people come in with a tank they bought at a "deal" for 70 bucks, need to have a valve re-worked, get a hydro and vis, and when they were done, they had $120 in a 20 year old tank, and they could have just grabbed a new one for about 10 - 15 bucks more...

10-20-2007, 14:13
Sorry....i am an idiot....in looking at a tank previously somehow i managed to think they were all 400 bucks and didn't see the ones that were cheaper...now tell me this...i'll only be certed for 60 feet initially and don't really plan on ever going beyond 100 feet regardless of my cert. status...how long will the aluminum 80 tanks keep me down for (on the average-i know there are variables). I am assuming time below is the primary difference between the 150 dollar models and the 300-400 dollar models...if that is not right...then i suppose i need a new question..LOL

10-20-2007, 14:25
Steel tanks cost more, AL tanks are more affordable.

As to how long you can stay down, depends on depth. Could be 20 minutes or more. Hard to say. You'll be at the low end for quite a while and get more time as you gain experience and your consumption rate goes down.

10-20-2007, 14:27
still i don't see the advantage to a steel tank v. al.....what are the bells and wistles i'm getting for my extra money....durability no doubt..anything else?

10-20-2007, 14:35
Aluminum is more bouyant, especially when empty. Steel tanks are negative all the time, just less negative when empty. This allows you to take some weight off your belt.

10-20-2007, 14:38
bingo thank you!!!....anyone ever use the colored tanks much and noticed a difference in the wildlife reaction...??

10-20-2007, 14:57
Yes. I have an AL80 in blue and my wife has an AL80 in black.

In less than a year, the color coat is banged up and will have to be removed soon. Salt water gets under the dings and corrodes the metal. Not good.

These are the very last colored tanks we will ever buy, AL or ST. We learned our lesson.

ScubaToys Larry
10-20-2007, 15:35
The fish don't care about the colors... they are more concerned with the big clumsy bubble blowing monster that is approaching - not the color of the tank on their back.

And as soon as you are comfortable, you should be about to get about 45 minutes or so from an Aluminum 80 Tank (http://scubatoys.com/store/detail.asp?PRODUCT_ID=AL80).

10-20-2007, 16:54
Cylinder selection is all about fit and comfort and need.

You choose a cylinder based on your physical size, air supply needs, exposure protection, fresh or salt water use etc. There are more than 40 different cylinder sizes and each serves a purpose. Capacity ranges from 4 cubic feet to 149 cubit feet. With the average diver using a cylinder for no-stop diving in the 50-117 cubic foot size.

While the most popular cylinder is the aluminum 80 it is not the most useful size. It floats when its empty and requires you to wear an additional 4-6 lbs of weight to balance it out. For big people its not enough gas, for small people its too long.

Previously owned cylinders can be a good deal if they are in good service, but if they are old, need a hydro test and a valve rebuilt you will spend a whole lot for an old item without a warranty whereas if you spent a little more you could get a new product. Aluminum cylinders are inexpensive (under $175 each) but then add on the cost of addional lead for balast.

Steel cylinders will typically cost more than aluminum cylinders due to the smaller manufacturing volume per size and the additional cost of materials. Steel cylinders will usually be more versitile than aluminum bottles as well.

Work with a good dive retailer to choose the correct size cylinder for you. Selecting a cylinder is just as important as selecting your mask, regulator, fins, bc etc. It's all part of the complete diving system.