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Q & A's with our experts. Q: I have just signed up for a SCUBA class and my instructor says . . . .

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Q: I have just signed up for a SCUBA class and my instructor says that masks from discount stores like Walmart are not adequate for diving. Is this true, or is he just trying to get an extra buck?

A: Generally speaking, it is true, and for several reasons. First, finding a good mask is one of easiest ways guarantee a comfortable, fun time underwater. Nothing spoils a dive faster than a constant, irritating leak in your mask seal, take it from me. Second, masks, like most items, come in varying levels of quality and are made from a variety of different materials. The best quality masks have tempered lenses and top-quality silicone skirts. Tip: Higher grades of silicone are virtually clear. Masks with opaque or solid white skirts, are generally made with a lower grade of silicone or PVC. Both low-grade silicone and PVC lack the flexibility to form an effective seal against your face and may be prone to leaking under water. Additionally, these cheaper materials will yellow with time. Additionally, it is very important to ensure that your mask has the features required for diving, like an accessible nose pocket, which allows for easy equalization of sinus pressure created by the surrounding water. The best way to make sure you’re getting a mask that is suitable for diving and fits your unique face is to purchase it from a retail assistant at a quality dive store.

Q: I use nitrox purely for safety by diving conservative air profiles. My question is this: If I have just one nitrox tank and my second tank is air, should I use the nitrox or the air on my second dive?

A: The reality is that it will probably make very little difference if you are diving conservative air profiles and using nitrox purely for physiological advantage. However, to be most conservative you should use the nitrox on the deeper dive. If both dives are to the same depth I would use nitrox on the second dive, because the equivalent air depth (or equivalent nitrogen depth) of the nitrox will be shallower than the dive on air. Consider this example: On a dive profile with two dives to 80 fsw and the second dive is completed on 36% nitrox, that dive would be equivalent to an air dive to 58 fsw, based on the EAD formula: [(FN2/0.79)(depth + 33)]-33 = EAD.

Q: Help! My husband’s mask always leaks. He has tried shaving his mustache but has quite deep cheek lines around his nose area and that seems to be the problem. What do you recommend?

A: You should look for masks that have large and very soft silicone seals. The larger seals place more surface area in contact with the contours of your husband’s faced and may provide a better seal. The softer silicone allows the seal to conform to those contours more easily. Do not make the mistake of over tightening the mask strap. Pulling the strap too tight may distort the shape of the seal and cause the mask to leak more instead of less.

Q: I am healthy female diver in my early 30s and my question is about contraceptive devices and diving. I am considering having my doctor prescribe an IUD to replace my oral contraceptives. Are there any special concerns with the use of these devices for divers?

A: This is a question best addressed by your doctor and I cannot answer it fully here. I checked with a Gynecologist who is also an active diver and she provides this general advice. The IUD itself does not create issues for diving in most women, so for most divers there would be no issues. As a diver you only need to be concerned about the usual precautions your doctor will discuss with you. She also advises that every case is different and that it is vitally important that you discuss ALL of your concerns with your personal doctor before deciding to have an IUD inserted. This includes your concerns about diving. If your doctor has concerns or lacks the knowledge necessary to advise you, have the doctor confer with the experts through The Divers Alert Network or the Undersea and Hyperbaric Medicine Society.

Q: I am pretty comfortable clearing my mask underwater, but I wear contacts and I often wonder what I would do if my mask was knocked completely off underwater. My instinct is to close my eyes to keep from losing my contacts, and with the mask off, it seems there are only two options: 1) open them and lose my contacts, or 2) have my buddy retrieve the mask for me. What do you recommend?

A: No matter how good your vision is on land, it will be horrible when you’re trying to see underwater without a mask. It is actually extremely rare for a diver to completely lose their mask underwater, but if you do, with or without contacts, it is unlikely that you will find it again unless it falls directly in front of you. Closing your eyes is the best way to keep from losing your contacts, so you would need to have your buddy readily available to help you find the mask. If not, you’d probably need to do a controlled ascent without it. You could also carry a spare mask in an accessory pocket on your BC.

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