Underwater World is the Philadelphia Region's Premier Scuba Shop and Training Facility!


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scuba shop, equipment and repair

dive training and education

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Philadelphia region dive shop
495 Easton Rd - Route 611 - Horsham PA 19044 - (215) 672-4180
STORE HOURS: Monday - Friday 1:00 - 9:00 · Saturday 10:00 - 6:00

Click here to contact us for more information and assistance





REGULATORS - How to make the right decisions.

As the keystone of safe diving, regulators are the single piece of equipment that brings out the most questions and stirs the most debates. In this brochure, we will try to demystify regulators for you, allowing you to make a reasonable decision on the regulator best suited for your needs.


Basically, what we want out of a regulator is air flow enough air under all conditions, and with little effort. There are several things that cause air flow to vary. First of all, it is important that you understand that air is a fluid, very much like water. If you cause it to turn corners or change direction, it will slow down. If you make an opening too small, it will restrict the flow, especially at lower pressures. (Where you may be able to force air through a small opening at 3000 psi, it will be harder to force air through that same opening when the tank pressure is 500 psi.) As we go deeper, the air becomes more dense, or thicker (Remember Boyle’s Law.) This makes it harder to move the air through the same size openings. A good regulator is designed to handle these problems better than an inexpensive regulator. This is done by producing a more finely designed and machined first stage. It is the first stage where the real action takes place. There are other tricks such as large diameter hoses and devices to create venturi flows in the second stage, that will also help the flow of air. Talk to the professionals at Underwater World and they will explain these features in detail.

PISTON OR DIAPHRAGM - Balanced or Unbalanced

Ah !! The perennial debate. Usually conducted by divers who really do not understand the real difference. First of all, let us dispel a common myth. There can be balanced or unbalanced piston regulators, but a diaphragm regulator is, by definition, a balanced regulator. You cannot have an unbalanced diaphragm. Without getting into the actual mechanics of it (We do that in our Equipment Specialist Course), you should know that a good balanced regulator will maintain its breathing characteristics as you go deeper or as your tank pressure drops. In an unbalanced regulator the changes are more noticeable. Why build an unbalanced regulator? It is a simpler design and less expensive to build. It will therefore will sell for less. Although an unbalanced regulator is perfectly safe to use, we generally recommend it mainly for pony bottle use only. That said, do you buy a balanced piston or a diaphragm regulator? There are some excellent regulators in both of the categories. We would recommend regulators such as the Scubapro Mk25/S600, the Aqualung Legend LX,or the Oceanic Delta 3/CDx5. Some regulators are equipped with hose swivels. Swivels on the first stage allows the regulator hose to follow the turn of your head without tugging at your second stage, which should rest comfortably in your mouth. These swivels do change the direction of air flow and they could affect the flow. "Captured" o-rings, as you find in a swivel, are usually pretty trouble free, especially if you have your regulator serviced at least once a year (Hint, Hint). And the airflow difference in a top-of-the-line regulator is negligible. Do you need swivels? No. But we do like them on our regulators.


Again, not a necessity, but nice to have. An adjustable second stage, as found on the Scubapro MK25/S600, the Aqualung Legend LX and the Oceanic Delta regulators, allows the diver to adjust the breathing effort of their regulator, even while on the dive. It is simply a knob on the second stage that turns. Turn it one direction and it may stop a slight free flow (saving you a trip to the shop), turn it the other direction, it makes your regulator breathe easier.


Aqualung, Scubapro, and Oceanic regulators all come with a lifetime warranty on parts. This means that you pay to get your regulator overhauled annually, and we charge any parts to them. It will definately save you a couple of bucks. (This, of course, is ONLY available if you purchase your equipment through an authorized dealer. It is important that if you are buying equipment that you are sure. You could check the manufacturers' web site if you have and doubts.) And with our Preferred Customer Program, if you purchase your regulator from Underwater World you will receive a $15 discount on your annual overhaul.


Now, it is starting to come down to your preferences. The big three in regulators are Aqualung, Scubapro and Oceanic. These are all American made and very popular regulators. This means wherever in the country (or the world) you wind up, you will be able to find parts for your regulator and people who can work on it. Buy a regulator made overseas, the parts must come from overseas. This can sometimes mean substantial delays. Stick to the home brands.


We, at Underwater World, believe that the best way to make a decision is to come into Underwater World and talk with our professionals. We will discuss the type of diving that you plan on doing and make a recommendation as to the best purchase for you. I tell my students that they should just find a dive shop that they trust (hopefully, that is us) and take advantage of the expertise of their personnel. There is no need for you to be a regulator expert. We can be that expert for you. Come in and see us. Or give us a call with any questions and we will steer you in the right direction.if you decide you need to buy on line, remember that Aqualung and Scubapro do not allow on-line sales. We can sell you Oceanic products through our Oceanic sponsored web site. Click here to enter that site.

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One of the most important decisions we make in choosing the proper diving equipment is the choice of our buoyancy compensator. We will try to help guide you through the many choices that you can consider.


Fit - Fit - Fit !! The bc is a fit item. There is no way around it. This is your most important consideration. It is like your mask. You can't pick out one that you like and then try to get it to fit. Figure out which ones fit and then choose from among them.


There are basically three types of flotation. Back-mounted. Flow-through. Wrap-Around. Many people criticize the back mounted bcs, stating that they will push you face down in the water when you are at the surface. It is true that there is more of a tendency towards this, but a simple shift in your body position will counteract it. As a matter of fact many of our instructors dive with this type of bc. The flow-through bc (primarily the ScubaPro Stab Jacket), seems to be preferred only by those who were trained exclusively on them. The disadvantage is that the shoulders are not adjustable and therefore fit suffers. The wrap around jacket is the standard jacket used by most divers.


Although this is not a new idea, it is just recently that good weight integrated bcs have come on the market. And there are some real advantages to these bcs. For instance, when at the surface, most of us have noticed that the bc tends to ride up on us. That is because the bc, full of air, is buoyant. The diver with a weight belt wrapped around him is negative. He is pulled out the bottom of the bc by the weight belt. With a weight integrated bc, the diver is actually buoyant and at the surface tends to float up into the bc. This should eliminate that tendency to ride up. We also eliminate the problem of the weight belt loosening up and slipping off our waist as our suit compresses. And finally it eliminates the problem of the weight belt turning on the body so that the buckle is no longer within reach. It seems that the advantages favor the proper weight integrated bc.


You often hear the comment that you need more lift in cold water than in warm water. I assume the thought is that you are wearing more stuff (i.e. more weight, thicker suit) in cold water. However, remember that you should be starting your dive neutrally buoyant, whether in warm or cold water. At that point 20 pounds of lift is 20 pounds of lift. It will hold you in the same position either way. The only real reason to have more lift is if you are diving in rough water and want to be held higher out of the water. But remember that a bladder that gives you more lift is larger and, therefore creates more drag. I would not worry too much about comparing lift.


Another item that has been around for several years but is only lately refined to a point where we are willing to recommend it is the integrated alternate air source and power inflator. This unit is designed to replace your octopus and eliminate one hose from your regulator. Your octopus actually becomes part of your power inflator. When using this type of alternate air source you would give your buddy your primary and then you would breath off the alternate air source. The disadvantage is that both divers have their regulators out of their mouths during an emergency. However, if you dive with the same person regularly and practice occasionally, there should not be a problem.


Today we have bcs that are designed specifically for women. Believe it of not it really does make a difference. We carry several different women's models, such as the Seaquest Diva, the Scubapro Ladyhawk, or the Oceanic Isla. These bcs are designed so that they are shorter waisted and sit above the women's hips. The shoulder straps are designed to carry the weight of the tank in a way that they do not cross the woman's breasts as the straps on a man's bc does.


Although most bcs come with some accessories to hold your octopus and console, we have generally found that after-market devices seem to work better. Many of the devices that come with the bc hold the octopus and console by the hose. This allows it to dangle too far from the body. We have other devices that will hold your octopus by the mouthpiece or the console by the gauge itself. This is definitely a better way to do it and the cost is usually less than $5.00 for these devices.


Maintaining your bc is not very difficult. You should wash it off in fresh water whenever you use it, especially in salt water or chlorine. Also make sure that you empty any water out of the bc. To do this, inflate the bc, turn it upside down, and press the oral inflator button. If you have gotten salt water in your bc, you should rinse out the inside. If you do not the water will evaporate inside the bc leaving behind salt crystals. These salt crystals are hard and sharp and can actually puncture the bc bladder, usually with many tiny holes. To prevent this just pour water in through the inflator, swish it around, and dump it out. It is also a good idea to use BC Wash to clean out the inside of your bc occasionally. This not only dissolves the salts; it prevents any "growth" from occurring. Finally, have your bc overhauled annually as you do with your regulator.


We really prefer that you come into the store for the best selection and to get fitted properly. AS we said at the beginning, fit - fit - fit!! If that just doesn't work for you, we have an Oceanic authorized on-line shop wher you can still purchase for us, receive the same warranty and the same Underwater World service, and have it shipped directly to your home. Just Click here.

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KODAK SEA PROCESSING - Get Color that's to dive for.

See your underwater memories the way they looked. Kodak Sea Processing brings your dive pictures alive.


Using digital processing, color correction, and contrast expansion, Kodak Sea Processing takes your underwater pictures from boring to brilliant. Underwater photos need special treatment for best results. Kodak Sea Processing does it, traditional processing doesn't.


Digital enhancement technology from Kodak Sea Processing does wonders for pictures on land and sea. You'll get sharper brighter photos than ever before. Prints are easy to handle and share and are printed on Kodak Royal Paper.


See your pictures at a glance with the convenient index print that comes with each roll processed. And your negatives come in protective sleeves.


Kodak Sea Processing can take your previously processed negatives and bring them alive with its special techniques. You will be thrilled. Bring or send us your old negatives and we will take care of them for you.


Another option to bringing your film to us is to use Kodak Sea Processing self mailers. Available from Underwater World, you place one roll in each mailer and drop them in the mail. The processed prints will be delivered directly to your home.


Kodak Sea Processing can take your negatives and put them on mouse pads, hats, t-shirts, mugs and more. You can decorate you home or office or give them to your friends to remind them what a great photographer you are. Or have us put them on CD and you can e-mail them to your buddies. The possibilities are endless. techniques. You will be thrilled. Bring or send us your old negatives and we will take care of them for you.