INTRODUCTION
This simplified guide is intended to teach the fundamentals of the
proper aeration and oxygen techniques in keeping live bait, and "catch & release" fish,
alive and healthy in live wells.
The advantages as well as disadvantages of many types of
aeration will be discussed.
UNDERSTANDING
THE CONCEPT OF AERATION
There are many misconceived ideas about aeration.
Two common fallacies are:
Large live wells are required to sustain a large quantity of fish.
Large live well pumps are needed to move large quantities of water through the
live well to keep live bait and fish alive.
To understand what is really needed for proper aeration, it is best
to take a parallel look at ourselves and fish.
FACTS FOR HUMANS
If we were enclosed in a large airtight room we would be able to breathe for
many hours before we would consume all the oxygen.
If we were in an airtight closet, the oxygen would be consumed a lot quicker.
If we were swimming underwater without a snorkel, the oxygen in our lungs would
be consumed very quickly.
In all cases, without additional oxygen we would eventually expire!
However, we could stay alive indefinitely, if we could use a
breathing tube or snorkel that was in contact with outside fresh air or oxygen. It would
not matter about the size of the container or the quality or air that
surrounded us.
FACTS FOR FISH
If we enclosed a fish in a sealed, 1,000
gallon tank, it would survive for a long time before consuming all the
oxygen.
If we enclosed the same fish in a sealed
10 gallon tank, the oxygen would be consumed more quickly.
If we removed the same fish from the tank and
placed it on a table, the fish could live for an extremely short
time.
In all cases, without additional oxygen the
fish would eventually die.
However, our fish could stay alive indefinitely if
we could put oxygenated water through its gills and keep it wet. It
would not matter about the size of the tank.
AN AERATOR IS TO A FISH,
WHAT A SNORKEL IS TO US!
SIZE
OF AERATORS AND SNORKELS
FACTS
It is more difficult to breathe through a straw than through a large snorkel.
A small or ineffective aerator cannot provide as much oxygen in the water as a
larger or more effective one.
If an aerator can provide enough oxygen in the water for the fish to breathe, it
doesn't matter how much water surrounds the fish![b] The only reason that water must be
changed occasionally in live wells is to remove ammonia.
The smaller the container of water, the more frequent the changing.
[/b]
BASIC
REQUIREMENTS OF AERATION
There are two major considerations in aeration.
1. The gentleness and direction of water flow
2. The size and amount of the air bubbles
3. The temperature of the water
GENTLENESS
AND DIRECTION OF WATER FLOW
FISH
THAT SWIM IN SCHOOLS
Delicate bait such as shad, green-backs and croakers will not survive a day
of fishing unless the water flow in the well is soft and gentle. Turbulent
water will damage the bait and force them to work against the current. Ideal
water flow within the well should be approximately 1 to 2 MPH, and in a
circular motion. This will allow fish to school and provide a smooth flow of
water over and through their gills. If the water flow is excessive, bait
tire quickly and will not be lively. Keep water flow as low as possible,
with fish swimming in a stationary position within the tank.
SHRIMP AND FISH THAT DO NOT SCHOOL
Species that do not school do not need a circular or oval container. Keep
water flow to a minimum for fish such as bass, redfish, crappie, bream, and
walleye.
For
shrimp, provide material in the well so they can cling and not be swirling
about the well and become damaged. Leave a dip net in the well, or tie a
stone in a piece of cloth such as burlap.
SIZE
AND AMOUNT OF AIR BUBBLES
Take a look at at the air bubbles produced by an aquarium aerator. Watch
how quickly the bubbles rise to the surface. They provide little aeration, but are
aesthetically pleasing to watch. Bubbles must remain contacting the water, if they are to
do the job properly. A good rule of thumb is: The smaller the bubble, the longer it will
remain suspended in water to dissolve.
WATER
TEMPERATURES
The
warmer the water, the less oxygen it will hold. Fish will deplete the oxygen
quicker as the water warms, and poor aerators will maintain less fish.
Colder water will hold more oxygen. Water frozen in a plastic bottle will
lower temperatures and keep the chlorine out of the tank.
Use an
aquarium thermometer to compare temperatures. Keep temperatures within eight
degrees Farenheit between water in the well,
and
water outside the boat.
CAUTION:
Placing fish in different temperatures quickly will shock and kill them. It
is best to place fish in the same water and temperatures where they were
caught.
A Lesson in Air Bubbles
by
Bob Heideman
of
Aquatic Eco-Systems, Inc.
The smaller the air bubble, the more slowly it will rise, giving it more time
to dissolve in the water.
Due to the higher density of salt water, air bubbles are usually smaller
in salt water than in fresh water.
A large 20mm bubble has a volume of 4.19 cm3, and a surface area of 12.6
cm2.
You could make 260 small 3mm bubbles from the large bubble. They would
have a total surface area of 83.6 cm2. This is 6.6 times the surface of the 20mm bubble.
The small bubbles, can theoretically aerate 6.6 times as much water with
the same amount of air.
Knowing the importance of air bubble size, the effectiveness of different
aerator systems becomes readily apparent!
LIVEWELLS
Livewells come in many shapes and sizes. Oval or round tanks provide the
best circulation. However, rectangular or square wells are satisfactory if
there is a directional discharge into the well. The directional discharge
will induce the more desirable circular motion.
Species that do not school, do not need a circular or oval container. Keep
water flow to a minimum for fish such as bass, redfish, crappie, bream and
walleye. They do not need a water flow for survival.
For
shrimp, provide material in the well so they can cling and not be swirling
about the well and become damaged. Leave a dip net in the well or tie a
stone in a piece of cloth such as burlap.
AIR VERSUS
OXYGEN
Oxygen
will maintain higher quantities of fish, but extra care must be taken when
using pure oxygen. To understand the fundamentals or air versus oxygen, each
should be individually discussed.
A
human breathes in oxygen and gives off carbon dioxide (CO2). The CO2 is then
dissipated into the atmosphere.
A fish
breathes in oxygen from the water and gives off CO2. The CO2 is absorbed
into the surrounding water. The CO2 is then dissipated into the atmosphere
through the process of aeration.
An air
bubble as it passes through water has the ability to put oxygen into the
water and also absorb CO2 as it passes slowly to the surface. The bubble
then pops at the surface and the CO2 is dissipated into the atmosphere. The
smaller the bubble, the longer it remains in the water to exchange oxygen
and CO2.
An
oxygen bubble will insert a higher percentage of oxygen into water than a
normal air bubble. This allows for higher quantities of fish in a given size
of container, or it will make bait fish lively. However, an oxygen bubble
does not have the ability to absorb CO2. As the fish eliminates CO2 in it’s
body, there will be a build-up of CO2 in the livewell water. When the
percentage of CO2 equals that of the fish, the fish will be unable to expel
the CO2 and absorb the enriched oxygenated water. If a closed livewell does
not have the ability to aerate and remove the CO2, the fish will suffocate.
Water at the surface of your livewell that is in contact with air will
produce aeration and may be sufficient to remove CO2 without introducing
other forms of aeration.
CAUTION: TOO MUCH OXYGEN WITHOUT
REMOVAL OF CO2 MAY KILL
YOUR FISH!
USING OXYGEN
SYSTEMS
Theory suggests that large percentages
of oxygen in water will turn your bait into star performers and
attract more fish.
To increase the oxygen percentages
higher than what would be normally found in the water entering your
livewell, the intake pumps to the well should be turned off.
Otherwise, oxygen enriched water produced by your oxygen system will
be dumped overboard and defeat the purpose of producing livelier bait.
USING AERATORS
WITH OXYGEN SYSTEMS
Aeration
systems should be turned off when enriching water with higher than ambient levels of
oxygen. When aerators are on, they will try to keep oxygen levels at normal
conditions. You won't produce livelier bait, but they will remain healthy,
Remember that oxygen cannot absorb and dissipate CO2, so high levels of CO2
in the water will eventually kill your bait. Watch your bait occasionally to
see if they start to stress. If stress occurs, immediately start your
aeration system or change the water in the livewell.
One recommendation when fishing tournaments, is to
keep aeration and oxygen systems both operating until 20 minutes prior to
reaching your fishing area. Then turn off the aeration or fill pumps to
allow oxygen levels to build in the water, and time for the bait to increase
physical activity. CO2 levels will be low in the livewell, so more time can be spent fishing rather
than observing your bait. When changing areas, replace the water or start
the aerator.
FISHING
OXYGEN INFUSION SYSTEMS
Fishing oxygen infusion systems are
designed for use in a marine environment. They are the
latest technology for anglers to maintain bait and catch. Oxygen systems
have been used by large commercial fish farms and aquariums for many years.
The technique is now available for all anglers.
OXYGEN
REGULATORS, DIFFUSERS, AND CYLINDERS
Fishing
regulators use a CG540 valve to connect the regulator to the oxygen
cylinder. The cylinder can be filled at most welding shops. They are
never used for medical purposes.
Marine grade fishing regulators are
exposed to the marine elements and are made of brass with nickel plating.
Anodized aluminum regulators with internal brass , designed with non-rusting
components and designed to prevent intrusion of spray and humidity can be
used and are a good alternative choice for many anglers. They can be either a needle valve or rotating barrel with preset
openings. The rotating barrel is the preferred choice. Only small amounts of oxygen is needed to maintain fish so the
first settings are very small.
Never lubricate or spray your
regulator. This will contaminate the regulator and may render it
inoperative.
The diffuser
is probably the most important item of your equipment. Inexpensive air
stones waste precious oxygen. Bubbles are large and do not maintain contact
with the water long enough, and are little use to good oxygenation.
Diffusers are made of ceramic with tightly formed pores. The require 25 to
35 lbs of pressure to force the oxygen through ceramic pores, resulting in
micro-fine bubbles. The bubbles are so small that they stay suspended in the
water and the water absorbs the oxygen. Ceramic diffusers will give many
years of service. If the pores clog at the surface due to impurities in the
water, a light sanding on the ceramic surface will generally solve the
problem.
Oxygen cylinders usually come in three sizes, made
of aluminum and powder coated to prevent rust spots on your boat, and use the CG540 welding
valve. Use the largest cylinder that will fit on your boat
comfortably. The cost of refilling a cylinder is generally the same, so there
are substantial savings if you are fishing frequently.
Some welding shops have programs where
you can purchase your cylinder and trade it for another filled cylinder
immediately. The only disadvantage to this type of program is that the
cylinders are steel and care must be taken to prevent rust spots on
your boat.
Care must be taken to secure the high
pressure cylinder securely to your boat. Do not
secure your cylinder in a closed compartment.
Oxygen trans-fills
can be used to fill your smaller boat cylinders from
larger welding oxygen cylinders to reduce oxygen costs. Care must be taken
to SLOWLY crack open cylinder valves to allow
oxygen to transfer SLOWLY. TRANSFERRING OXYGEN TOO
QUICKLY MAY OVERSTRESS YOUR CYLINDERS AND CAUSE HEAT BUILDUP ON YOUR
CYLINDER. To ensure good safety practices and prevent errors, use
trans-fills that have slow filling orifices.
Warning: Not for medical use.
ALWAYS FOLLOW GOOD
SAFETY PRACTICES WHEN USING OXYGEN!
Pure oxygen is not an
explosive. It is an oxidizer and allows things to burn more quickly. Never
smoke or have an open flame in the proximity of pure oxygen.
OXYGEN
GENERATORS
Oxygen generators are a new innovation
to the fishing industry. In lieu of a regulator, diffuser, and high pressure
cylinder, the oxygen generator takes outside air and filters it to produce
90% pure oxygen.
Oxygen
generators operate with low pressures, so the delivery system must be
different than ceramic diffusers that require high pressures to produce the
micro-fine bubbles.
When the low pressure pure oxygen is
fed into the air tubing of a KeepAlive Infusor, the micro-fine bubbles equal
that of a ceramic diffuser.
The advantages of oxygen
generators are:
1. Low pressure safety on a boat.
2. Mixing the oxygen at the impeller of the KeepAlive Infusor allows a
circular movement of water in the well for proper schooling of bait.
3. The use of a T connection in the air line allows different mixing
of pure oxygen and air to reduce CO2 build-up.
SPRAY BAR AERATORS
Spray bar aerators add oxygen to the water by jetting small streams of
water into the surface. Some air is absorbed into the spray as it passes from the spray
bar to the water surface, and when the spray strikes the water surface, air bubbles are
injected into the water. For the most part, these bubbles are rather large.
Jets of water from spray bars are generally harsh to delicate bait. Their
protective coating and scales are easily removed, and their survival is drastically
reduced.
Spray bars are an inefficient aeration system, and should be used only on
the hardiest bait.
AIR STONE AERATORS
Air stone aerators are an inexpensive way to keep bait alive in small
containers. They are quiet and gentle, but because their bubbles are typically larger,
they need a greater amount of bubbles for a large amount of bait.
Air stone aerators do provide gentle aeration, but they sustain less bait
per unit of air than aerators that produce smaller bubbles.
Most bubble aerators use C or D cell batteries.
Operational costs can be expensive.
VENTURI AERATORS
This is the much copied, old aeration technology. They can be purchased as
a floating aerator or a bottom aerator with suction cups.
The fast-moving water at the output of the pump creates a
vacuum, which
suck air into the pump output. This system typically provides larger amounts of smaller
air bubbles than previously discussed aerators.
Some models damage bait due to the high speed of water from the pump
output.
THRU-HULL PUMPS
Thru-hull pumps provide a constant flow of new water into the livewell and
eliminate the problems of heat and ammonia build-up. As long as clean water is available,
more bait can be placed in a given amount of water than with any of the previously
discussed systems. However, when entering water that is less than ideal for delicate bait,
care must be taken to secure the intake water. By utilizing a combination of the thru-hull
pump with other aeration methods, bait can remain healthy and lively for longer periods of
time.
KeepAlive
Oxygen Infusor
Systems
The KeepAlive
OXYGEN INFUSOR
is a new,
revolutionary oxygen infusion system
GUARANTEED TO OUTPERFORM ALL OTHERS !
They might look like the competition, but their superior technology is completely
different. Air is infused with the water at the pump impeller. The micro-fine bubbles
produced, are sent gently out of the pump and into the livewell, containing life giving
oxygen.
The KeepAlive
OXYGEN INFUSOR
is specifically
designed for delicate shad, greenbacks and white bait. The millions of micro-fine bubbles
are so small that they remain suspended in the water longer thus providing more oxygen for
your bait and catch. Our smallest model will aerate from a 5-gallon bucket up to a
55-gallon drum or livewell, gently and efficiently.The KeepAlive
OXYGEN INFUSOR will virtually
disappear in a mass of micro-fine bubbles when used in salt water.
The water speed is controlled by it's Air Control Center
to allow fish to school in a stationary position.
The KeepAlive
OXYGEN INFUSOR
isavailable as a bottom infusor with suction cups, a
floating infusor, or thru-hull infusor. Conversion kits are available to convert your Rule
bilge pump or Rule livewell pump to the exciting KeepAlive technology!
The KeepAlive
OXYGEN INFUSOR is an investment
that will save you time and money by keeping your bait healthy and lively longer than any
other comparable aeration system. . . . GUARANTEED!
Don't let your fishing trip end
before its time,
just because your bait did!
Make
KeepAlive a part of your fishing gear!
KeepAlive
. . . the newest technology in aeration and oxygen systems!
