The Basics

Most UV units are designed to lie on a flat surface.  I mounted mine on the wall behind my aquarium about 6 or so inches above the water level.  This is important because it will help to regulate the rate at which the water flows through the unit and back into the tank by gravity, increasing the length of time the water is exposed to the UV light, which in turn, maximizes the kill time.  The longer the water is in contact with the UVS the more pathogens are destroyed.  They are killed in the following order from those needing the least amount of kill time to those needing the longest....bacteria, viruses and most common parasites (requiring around 15,000 microwatts/second/cm²), algal cells (requiring around 22,000 µW/sec/cm²) and finally, protozoa (requiring around 45,000 µW/sec/cm²).  Fungi come in all shapes and sizes and will fit into all of these categories.

The UVS has two ports, an inlet and an outlet.  These are interchangeable on most units.  The inlet and outlet are threaded ports that are connected to the tubing by adapters or connectors that screw into the ports.  The tubing from the inlet runs into the tank to the pump.  The pump should be placed at the very bottom of the tank without sitting in the substrate.  The reason for this being twofold:

1. Water drawn into the pump intake is from the region where most of the pathogens reside.
2. This position increases the head pressure on the pump, which decreases the rate of flow as water is pumped against gravity to the UVS.  This increases the water's contact time with the UVS maximizing kill time.

What You Will Need and Tips on Finding/Using it:

• UVS recommended brands are Aquanetics or Aqua Ultraviolet, although most brands work equally well.

  Aquanetics

  Aqua Ultraviolet

• If your tank is under 20 gallons, you should get an 8-watt unit.  If the tank is between 20 and 200 gallons get a 15-watt unit, and anything over 200 gallons, go for the 25-watt model or larger.  The reason for this is that the larger the unit the more kill-chamber space, and consequently, the more water comes in contact with the bulb.  This further maximizes kill time, and allows you to get your tank's volume through the unit faster.

• Powerheads should be sized according to tank size and UVS wattage. For an 8-watt UVS, the flowrate of the pump should be at a maximum of 90g.p.h., with the optimum size being 50g.p.h.  For a 15-watt unit, the flowrate of the pump should top-out at around 150 to 200g.p.h., with the optimum being around 90g.p.h.

• ½ or ¾ inch tubing depending on the size of the intake and output ports on the UVS.  The Aquanteics uses ½ inch and the Aqua Ultraviolet uses ¾ inch.  I prefer the tubing sold at aquarium supply stores over tubing sold in the plumbing section of home improvement centers because it is more flexible and thus easier to work with.  It may be a little more expensive.  Buy extra, it can always be used as a siphon later.

• Thread/barb connectors AKA "insert elbows", "insert adapters" or "hose anchor fittings".
  

  These look like plastic tubes that are either straight or elbow shaped with ridges (barbs) on one end and threaded like a screw on the other end.  They come in a variety of sizes that fit the inner diameter of the tubing.  So if you get ½ inch tubing you will need ½ inch connectors.  These secure the tubing in place.  They also come with different thread sizes.  Take your UVS with you to the store and try them to make sure you have the appropriate thread size to fit the UVS ports.  You can get them anywhere that sells plumbing, irrigation or aquarium supplies.  I would recommend getting 2 of each shape.  Depending on where your unit is placed in relation to your tank a straight or elbow shape may facilitate the ease with which you are able to get the tubing into the tank.  You might not be able to figure this out until you start working with the tubing.  Remember, running out to the store in the middle of your project is a real drag!

• Teflon Tape to wrap the threaded end of the thread/barb connector to ensure a water tight seal.

• Measuring Tape

• Sharp sissors, pocket knife, or some other sharp tool to cut the tubing.  Be really careful cutting the tubing.  Getting cut mid project is an even bigger drag than having to run out to the store.

• Another connector may be needed to fit the power head to the tubing.  This one needs to fit over the small elbow connector coming out of the pump's outflow and into the tubing that leads to the UVS.  The problem here is that each end of this connector has to be a different size.  I tried several in the store, but couldn't find any that worked.  So I improvised.  I used a straight connector/coupler with the same diameter openings and smooth ends connected to a small piece (about 1½" length) of tubing that was one size smaller than my main tubing.  You just need to make sure that all these connections are snug.

• A small piece of tubing one size smaller than your main tubing if you can't find the connector described in #8.  My main tubing was ¾ inch so I used ½ inch for this connection.

1. Decide where your UVS is going to lay or be mounted.  I mounted mine on the wall behind the tank.  I made 2 slings with plumbers tape to hold the UVS and hung those from 2 cup hooks.

2. Decide which shape thread/barb connector you need to use based on the direction the tubing needs to come off the UVS to easily get to the tank.

3. Wrap the threaded ends of thread/barb connectors with Teflon tape.

4. Screw the thread/barb connectors into the intake and output ports of the UVS.

5. Hang or place the UVS where you decided.

6. Decide which port is going to be the inlet and the outlet.

7. Measure the distance from:
   1. the input thread/barb connector to the bottom of the tank.
   2. the output thread/barb connector to where you want the water to return to the tank.

8. Cut the tubing to the appropriate lengths.  I would cut on the generous side to leave room for error.  You can always trim it later.

9. Attach the cut pieces of tubing to the intake and output of the UVS.

10. Attach the coupler to the free end of the tubing coming from the input port of the UVS.
    1. If you found a single coupler one end fits inside the tubing.  The other end of the coupler will fit over the pump elbow.
    2. If not cut about a one inch piece of the smaller diameter tubing.  Attach that to one end of the remaining smooth coupler and then fit that into the tubing attached to the input port of the UVS.  The other end of this coupler will fit over the pump elbow when it is time to connect he pump to the tubing.

11. Take the powerhead and attach the elbow connector that comes with it to its output port directing it up and away from the intake.

12. At this point you are ready to start messing with the inside of the tank.  If your tank is already up and running with livestock and/or a lot of rock and decorations, the tubing is stiff and a bit difficult to work with, so I would recommend placing the fish in a large bucket of tank water with a heater and a small pump for water circulation.  This will avoid undue stress on the fish and prevent injury from an avalanche of rock, which is what happened to me.  Thank goodness none of my fish were hurt.

13. Place the power head as close to the bottom of the tank as possible without sitting it in the substrate.

14. Attach the end of the intake hose with its coupler to the elbow connector coming off the pump's output.

15. Place the return tubing attached to the outlet of the UVS into the tank.

16. Plug in the pump and UVS and allow it to run for 5 min to make sure there are no leaks.  If anything is leaking go back and tighten all your connections (be sure not to overtighten them though).

17. Turn off the pump and UVS and disconnect them.  Remove the intake and output tubing from the tank and take down the UVS.  Install the bulb as per the manufacturers instructions.  Replace the UVS following steps 13 through 15 again.  If there are no leaks and everything is running smoothly replace your fish with fresh saltwater.

18. Clean up or not.  This step can be put off for any amount of time depending on individual tolerance levels of yourself and those you cohabitate with.

19. Get yourself something to drink, give yourself a big pat on the back and sit down in front of your tank and enjoy your fish who will now be safer from all kinds of pathogens.