1. First Stage Leak

Where: From orifices and seams in the first stage housing.
Looks Like: Anything from an occasional bubble to a constant small stream.
The Problem: Wear and tear, or misadjustment of the internal parts during overhaul.
The Fix: Requires a technician.
Abort the Dive? Judgment call. It’s not likely to get worse quickly, and an occasional bubble might be tolerable for the day. If leakage increases, head for the surface.

2. Sherwood First Stage Bleed Leak

Where: From a single orifice of a Sherwood first stage.
Looks Like: A steady stream of very tiny bubbles.
The Problem: None. The bleed is intentional, a design feature of the dry piston-type first stage.
The Fix: Put your wrench away. Please!
Abort the Dive? Read my lips: there’s nothing wrong. The air loss, by the way, is minuscule—less than one breath in an hour.

3. Regulator Yoke Leak

Where: Between the tank valve and the high-pressure valve seat at the yoke.
Looks Like: Anything from an occasional bubble to a constant stream.
Sounds Like: Bubbling from almost-flat soft drink to a boiling kettle.
The Problem: The O-ring is dirty, cracked, worn, dry or the wrong size. Or the seat is nicked or dirty. Or the yoke is loose or not positioned correctly. Some DIN-to-yoke adapters make alignment of the yoke difficult.
The Fix: Remove the O-ring, clean and inspect the seat. Replace the O-ring with a new one, coated with just enough silicone to make it supple, not greasy. Tighten the yoke by hand, but firmly. No luck? Try a different tank.
Abort the Dive? Judgment call if the leak is very small, but it’s better to return to the surface and replace the O-ring.

4. Tank O-Ring Leak

Where: Between the tank valve and the high-pressure valve seat at the regulator yoke.
Looks Like: Other divers leap backward like they’ve seen a cobra.
Sounds Like: A Boeing 727 on thrust reversers.
The Problem: This usually happens when you first turn on the air, if you haven’t tightened the yoke enough. With the seat loose, pressure forces the O-ring to squeeze through the gap and tear, causing a loud escape of air. Another cause is using the wrong-size O-ring.
The Fix: A new O-ring and a stronger hand on the yoke screw.
Abort the Dive? Only until you calm down.

5. Hose O-Rings Leak

Where: At either end of any hose, between hose end fitting and whatever it screws into (first stage, second stage, BC inflator, SPG, etc.).
Looks Like: Anything from isolated bubbles to a constant stream.
Sounds Like: Nothing, or a faint hiss.
The Problem: The O-ring is dirty, cracked, worn, etc., as above. A leak immediately after an overhaul probably means the tech has not tightened the hose enough. If very loose, the O-ring can blow out with sound effects as above.
The Fix: Also as above. Where there is a swivel on the hose, be sure to separate between the swivel nut and the next nut, not between the two nuts and the SPG or second stage. How much to tighten the hose? One ungh on a short wrench.
Abort the Dive? If it’s the high-pressure hose to the SPG, it will be a small leak. As long as it doesn’t seem to affect the gauge, you can probably continue the dive. The high-pressure hose leak looks dramatic but involves very little air—the orifices are tiny. A low-pressure hose actually leaks more air, but you will still have time to return to the surface calmly and deal with it.

6. Worn Hose Leak

Where: Anywhere on any hose, but usually near the first-stage end fitting.
Looks Like: A tiny bubble, or chain of tiny bubbles on the surface of the hose. Or a steady stream of bubbles.
Sounds Like: Maybe nothing, maybe the fizz of ginger ale.
The Problem: The inner, woven layer of the hose has developed a weak area, usually through constant flexing. Air leaks to the outer, scuff-protecting layer of the hose, which has a chain of tiny relief holes along its length. That’s where the bubbles come out.
The Fix: Replace the hose. High-pressure and low-pressure hoses are not interchangeable, nor are low-pressure regulator and inflator hoses, though the industry is moving in that direction.
Abort the Dive? As with hose O-rings: The high-pressure hose is a judgment call, depending on how serious the leak is. Surface to replace a low-pressure hose.

7. Second Stage Leak (Due to excess intermediate pressure)

Where: From second stage exhaust.
Looks Like: Anything from a bubble every few seconds to a constant stream.
Sounds Like: Anything from a slow “glub, glub, glub,” to a pot at full boil.
The Problem: Several possibilities, same symptoms: (1) first stage out of adjustment and delivering too much pressure; (2) second stage “cracking pressure” too low.
The Fix: Dial back the second stage adjustment (if you have one) for more breathing resistance until the leak goes away. If you have to dial it back again and again as the dive continues, this is a sign of first-stage problems. By the way, flipping the minimum/maximum or venturi switch will have no effect. Have your reg serviced at the first opportunity.
Abort the Dive? if you can keep the leaking under control by adjusting the second stage. But if the problem is getting worse, head for the surface.

8. Second Stage Leaking Valve Seat.

Where: From second stage exhaust.
Looks Like: Same as excess pressure leak, above.
Sounds Like: Same as excess pressure leak, above.
The Problem: Sand, grit or corrosion under the second stage valve seat prevents it from sealing.
The Fix: Swirl the second stage through the water while working the purge (tank pressure must be on). The sand or grit may be washed out. Back on the boat, you may be able to remove the purge cover for better cleaning. Just be absolutely sure to put all parts back in the same order. If it’s a corroded seat, only a technician can make the repair.
Abort the Dive? Swirling may reduce the leak to manageable proportions. Otherwise, make a calm, normal ascent; air is not disappearing as fast as it sounds (though watch your SPG).

9. SPG Spool Leak

Where: Between the swivel fitting and the body of the submersible pressure gauge.
Looks Like: Anything from a steady stream of bubbles to a constant fizz.
Sounds Like: Anything from a boiling tea kettle to a roaring jet engine.
The Problem: The spool is the hollow stud on which the swivel mechanism mounts. Banging and dragging the SPG can bend or break the spool, or distort its O-rings.
The Fix: Requires some technical knowledge, but take heart: many dive boat captains, resort operators and dive shop folks can do it.
Abort the Dive? As with all high-pressure hose leaks, it looks and sounds worse than it is because the pressure is high but the volume is low. As long as the SPG is reading correctly it is a judgment call.

scuba-tanksSo why would anyone care about what’s stamped on a scuba tank? Maybe you’re in the market for a used tank and you want to get a sense of its age and history; maybe you want to make sure that guy at the dive shop isn’t trying to sell you a hydro before you actually need one; or maybe, being a gearhead, you’re just curious.
Standard tanks have standard crown markings. Other tanks, especially those of the steel variety, often will provide additional markings to indicate tare weight, maximum test pressure, carbon dioxide capacity, etc. The following markings were taken off an everyday aluminum 80 pulled from ScubaLab’s tank inventory; these types of markings can be found on virtually any tank.

Breaking the Code:

TC-3ALM-207 – Canadian regulatory authority markings.

TC = Transport Canada (showing the tank meets Canadian specifications).
3ALM = Canada’s specification code for 3-gauge aluminum.
207 = the tank’s service pressure (also referred to as working pressure), expressed in bars.

DOT-3AL-3000 – U.S. regulatory authority markings.

DOT = Department of Transportation (showing the tank meets U.S. specifications).
3AL = U.S. specification code for 3-gauge aluminum.
3000 = the tank’s service pressure (also referred to as working pressure), expressed in psi.


This particular tank’s unique serial number.


LUXFER = the tank’s manufacturer
10 = Month of manufacture
A = Inspection code symbol
05 = Year of manufacture
SO80 = Luxfer’s model/part number for this cylinder, indicating its capacity in cubic feet at normal working pressure (this is a standard 80 cubic foot tank; a SO40 would indicate a 40 cubic foot tank, SO30 a 30 cubic foot tank, and so on).

11 DO/69 12

Date of most recent hydrostatic test.
Got more information on scuba diving tank markings? Leave your tips in the comments below!

Mask Fitting Test

Mask Buyer's Guide

Snorkeling is the easiest way to access the beauty of the underwater world. If you have never snorkeled, or are looking for ways to improve your snorkeling experience, we have a few tips for you!

A big part of enjoying the marine environment in comfort and safety is having the right equipment. Properly fitted equipment is key to maximizing comfort and enjoyment. Here are a few tips to get you started:


Getting a high quality properly fitting mask is imperative to getting a good seal and avoiding mask leaks. Visit our Toronto store and we will gladly take the time to educate you on the benefits of certain features and materials and ensure that you are perfectly fitted for a mask. If you are not in the Toronto area you can view some of our recommended snorkeling masks online and call us and we will help guide you through you selection process.


Getting the right snorkel can have a big impact on your comfort in the water. You will want a snorkel with a purge valve for easy clearing and dry breathing. If you are inexperienced we recommend investing in a dry snorkel that allows no water in and allows you to focus on the beauty around you. Dive World has a large selection of snorkels for you to choose from and we are happy to walk you through all of your options in store or on the phone!


Getting the right fins is important for both comfort and safety. From a comfort stand point having fins that fit you perfectly is imperative to ensuring you do not get red marks or blisters on your feet. From a safety standpoint it is important to get the right fins that suit your skill set and snorkeling environment. Contact us and we will walk you through selecting a fin that will suit your needs best.

Snorkeling Vests

If you have concerns about your ability to swim or getting fatigued in the water, a snorkeling vest is the ideal solution for you. Snorkel vests keep you floating and reduce your energy output. They also increase your visibility to boats.

Know Your Limits

For the best snorkeling experience you should be aware of your personal limits. That means not going out into open water if the conditions seem too challenging. Going snorkeling with a tour is one of the best ways to access the best snorkeling sites while under the supervision of professionals who are familiar with local conditions.

If you are in the Toronto area you can always use our pool to try on your new equipment and get hands on tips and tricks from our experienced staff.

When you buy a brand new mask there is manufacturing residue left on the lenses that causes the mask to chronically fog up. Over time 10-20 uses this manufacturing residue will get worn away and then simply spitting in your mask will defog it perfectly.

That said you might still find your mask fogs up on some days and not on others. This is because impurities like dirt, or oil residue from your finger tips or even sun screen has gotten onto the lens and are causing it to fog up. In these circumstances what you need to do is simple clean the lens. This is why people recommend using baby shampoo. Using shampoo is just basically cleaning the lenses with soap. People recommend baby shampoo because it is non irritating to the eyes in the event that you do not rinse the mask properly.

Back to the issue of brand new masks and manufacturing residue on the lenses. If you are impatient and don’t want to wait 20-30 uses for this residue to naturally wear away you can use toothpaste (white preferable) to accelerate the degradation of this residue. Simply apply a dab of toothpaste to the inside of the lenses and spread it evenly with your finger tips, all over every millimeter of the lenses. Then leave the mask like that over night . The toothpaste should corrode the manufacturing residue and in the morning you can simply rinse the toothpaste off. When you go into the water you will still need to spit in your mask or use commercial defog to defog your mask. This should work! If it still fogs up a little, re-do the toothpaste step again. Unfortunately this is the process to breaking in a mask and getting it just right.

Finally, if you are REALLY impatient (like me) what you can do to solve this problem immediately is take a lighter and burn the inside of the lenses. This sounds scary but it is really easy. Watch this video to see what I am talking about Just be careful to not put the flame directly onto the silicone. Burn the entire surface of the lenses from the inside until you start to see the lenses get black/dirty or covered in soot. This is the residue of the manufacturing gunk getting burned off. Simple rinse that residue off after and use your mask remembering to again spit in it or use commercial defog.

This works I assure you. Just remember that regardless of what step you take, if you get dirt, oils or sunscreen on your lenses you will need to wash that off with soap (preferably baby shampoo) again before you use your mask. Watch this video again to summarize some of the stuff I talked about here.

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