Services
SCUBA Equipment Services Available at Hilltop-Diving
We offer a full range of SCUBA and skin diving services and instruction. Our service and repair department utilizes state-of-the-art testing equipment and the latest in specialty tools to keep your equipment functioning flawlessly. We use ONLY oxygen-compatible cleaning solutions and lubricants in our test facilities.
We are highly trained in the service and repair of the latest technologies and in a wide variety of older models as well. Don't trust your life support equipment maintenance to just anyone!
We are confident our quality and service will meet and exceed all of your expectations.
We offer a full range of SCUBA and skin diving services and instruction. Our service and repair department utilizes state-of-the-art testing equipment and the latest in specialty tools to keep your equipment functioning flawlessly. We use ONLY oxygen-compatible cleaning solutions and lubricants in our test facilities.
We are highly trained in the service and repair of the latest technologies and in a wide variety of older models as well. Don't trust your life support equipment maintenance to just anyone!
We are confident our quality and service will meet and exceed all of your expectations.
Certified Tank Inspections

Controlled by the U.S. Department of Transportation:
Pressure vessels are regulated by the DOT for the safety of transport vehicles, their passengers and the environments through which they pass. Every scuba tank model must pass an initial DOT certification, then EACH manufactured scuba tank must pass a test before it can be sold. It is somewhat equivalent to space specifications, so this is an extremely well-controlled industry!
Hydrostatic testing:
After the initial test, the results are stamped into the body of the scuba tank, along with the date (year and month) it passed. After that, the tank must be retested hydrostatically every five years. The test for each tank is on file at the DOT, and the testing station must contact them to obtain the correct test specification. A common hydrostatic test is to pressurize the scuba tank to 5/3 of its working pressure and to measure the flexing of the tank walls. Five-thirds of a 3,000 psi working pressure means that the tank will be pressurized to 5,000 psi. This is done by replacing the valve with a special hydraulic testing connection and filling the scuba tank with water under pressure – NOT air! Air would be too explosive if the tank were to let go during the test, as it sometimes will. Because water cannot be compressed, the tank cannot explode if it fails. Testing is done inside an armored containment vessel. The tank is also under water, and they measure the amount that a water column rises as the tank is pressurized. This measures the amount of tank expansion. The water inside does not expand, but the aluminum or steel tank casing certainly does! They are looking for tanks that DO NOT expand as much under pressure, indicating that their walls have been work-hardened over the years. Like a piece of steel that is repeatedly flexed, the tank walls get hard to the point that they may suddenly fail with a snap. This is EXTREMELY rare outside the testing station. When it DOES happen, it’s almost always fatal to people standing close by.
You know it when they fail:
When a tank fails during hydro, it’s usually the valve threads that let go. It sounds like a loud “whump” if you are in the building when one fails. The other thing that sometimes happens, but not as often, is that the bottom of the tank bursts open. This is due to corrosion. If the tank fails to flex enough during the test, it can never be filled with air again, and no dive shop will do so. It will not be stamped with a current test stamp (one within the past five years) and is “out of hydro” as far as any dive shop is concerned. One possible use for a failed tank is to cut off the bottom with a carbide saw (a lengthy process!) and hang it far downrange on a rifle range to be used as a gong.
The annual visual inspection:
The annual visual inspection is performed by a dive shop. They let the air out of the tank and removes the valve to have a look inside. They’re looking for signs of corrosion and will refuse to put a visual inspection sticker on the tank if they find any. These stickers are paper or plastic and they stick to the tank. Every dive shop I have used has refused to fill a tank that has an out-of date inspection sticker. But they can do the inspection right there – the tank does not have to be sent to an outside party. They open the valve a little to slowly let the air out. This prevents condensation from rapid cooling. It takes 12 hours or more for a tank to bleed down – especially since airgunners seldom let their tanks drop below 2,000 psi. Let the dive shop bleed your tank for you; they know what they’re doing!
We invite you to focus on the fact that Diving or Snorkeling is an AWESOME visual experience! If you need optical correction on land, in order to see clearly underwater and enjoy the best possible adventure, take advantage of our ‘Custom Lens Masks’. Whether you are viewing beautiful coral reefs or tropical underwater landscapes, a custom lens mask will be an essential piece of your equipment.
A poorly fitting mask that leaks or is uncomfortable can ruin a dive. A mask which fits in the store may not fit under all diving conditions. Sometimes style, quality, and features must be sacrificed for a mask with proper fit and comfort.
Whether you are snorkeling or scuba diving, there are a few basic things to remember when selecting and preparing a mask for your next snorkeling or scuba diving adventure. The reason you are shopping for a mask is so you can enjoy the awesome beauty and serenity of the underwater world. If your mask is uncomfortable or leaks constantly, an otherwise wonderful experience can be ruined. Scuba divers should look for the largest field of vision a mask has to offer with the lowest internal volume so that the mask is easier to clear. Snorkelers should look first for fit and comfort, then consider style and color. How do you know what to look for when fitting a mask? Ask one of our highly trained staff, we would be happy to help.
Pressure vessels are regulated by the DOT for the safety of transport vehicles, their passengers and the environments through which they pass. Every scuba tank model must pass an initial DOT certification, then EACH manufactured scuba tank must pass a test before it can be sold. It is somewhat equivalent to space specifications, so this is an extremely well-controlled industry!
Hydrostatic testing:
After the initial test, the results are stamped into the body of the scuba tank, along with the date (year and month) it passed. After that, the tank must be retested hydrostatically every five years. The test for each tank is on file at the DOT, and the testing station must contact them to obtain the correct test specification. A common hydrostatic test is to pressurize the scuba tank to 5/3 of its working pressure and to measure the flexing of the tank walls. Five-thirds of a 3,000 psi working pressure means that the tank will be pressurized to 5,000 psi. This is done by replacing the valve with a special hydraulic testing connection and filling the scuba tank with water under pressure – NOT air! Air would be too explosive if the tank were to let go during the test, as it sometimes will. Because water cannot be compressed, the tank cannot explode if it fails. Testing is done inside an armored containment vessel. The tank is also under water, and they measure the amount that a water column rises as the tank is pressurized. This measures the amount of tank expansion. The water inside does not expand, but the aluminum or steel tank casing certainly does! They are looking for tanks that DO NOT expand as much under pressure, indicating that their walls have been work-hardened over the years. Like a piece of steel that is repeatedly flexed, the tank walls get hard to the point that they may suddenly fail with a snap. This is EXTREMELY rare outside the testing station. When it DOES happen, it’s almost always fatal to people standing close by.
You know it when they fail:
When a tank fails during hydro, it’s usually the valve threads that let go. It sounds like a loud “whump” if you are in the building when one fails. The other thing that sometimes happens, but not as often, is that the bottom of the tank bursts open. This is due to corrosion. If the tank fails to flex enough during the test, it can never be filled with air again, and no dive shop will do so. It will not be stamped with a current test stamp (one within the past five years) and is “out of hydro” as far as any dive shop is concerned. One possible use for a failed tank is to cut off the bottom with a carbide saw (a lengthy process!) and hang it far downrange on a rifle range to be used as a gong.
The annual visual inspection:
The annual visual inspection is performed by a dive shop. They let the air out of the tank and removes the valve to have a look inside. They’re looking for signs of corrosion and will refuse to put a visual inspection sticker on the tank if they find any. These stickers are paper or plastic and they stick to the tank. Every dive shop I have used has refused to fill a tank that has an out-of date inspection sticker. But they can do the inspection right there – the tank does not have to be sent to an outside party. They open the valve a little to slowly let the air out. This prevents condensation from rapid cooling. It takes 12 hours or more for a tank to bleed down – especially since airgunners seldom let their tanks drop below 2,000 psi. Let the dive shop bleed your tank for you; they know what they’re doing!
We invite you to focus on the fact that Diving or Snorkeling is an AWESOME visual experience! If you need optical correction on land, in order to see clearly underwater and enjoy the best possible adventure, take advantage of our ‘Custom Lens Masks’. Whether you are viewing beautiful coral reefs or tropical underwater landscapes, a custom lens mask will be an essential piece of your equipment.
A poorly fitting mask that leaks or is uncomfortable can ruin a dive. A mask which fits in the store may not fit under all diving conditions. Sometimes style, quality, and features must be sacrificed for a mask with proper fit and comfort.
Whether you are snorkeling or scuba diving, there are a few basic things to remember when selecting and preparing a mask for your next snorkeling or scuba diving adventure. The reason you are shopping for a mask is so you can enjoy the awesome beauty and serenity of the underwater world. If your mask is uncomfortable or leaks constantly, an otherwise wonderful experience can be ruined. Scuba divers should look for the largest field of vision a mask has to offer with the lowest internal volume so that the mask is easier to clear. Snorkelers should look first for fit and comfort, then consider style and color. How do you know what to look for when fitting a mask? Ask one of our highly trained staff, we would be happy to help.