PracticalAquaponicsForEveryone2

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Issue

#2

The

Bi-monthly

Aquaponics

HQ

e-Zine

May

2007

In This Issue In This Issue

•

• Aquaponics HQ...the changing face of APAquaponics HQ...the changing face of AP 11 •

• Running your system using TimersRunning your system using Timers 11 •

• My grow beds and fish tank are set upMy grow beds and fish tank are set up

…...what do I do now? …...what do I do now?

2 2

•

• What should I feed my fish?What should I feed my fish? 22

•

• Duckweed Duckweed - - Fast Fast Food Food for for FishFish 44 •

• How to Build a Grow Bed StandHow to Build a Grow Bed Stand 66 •

• How many fish can I keep in my tank?How many fish can I keep in my tank? 33 •

• Why I chose Silver Perch...Why I chose Silver Perch... 33

Aquaponics HQ

The Changing Face of Aquaponics

The response to the first issue of the Practical The response to the first issue of the Practical Aquaponics magazine was amazing; so much Aquaponics magazine was amazing; so much so that it caused us to re-examine the best so that it caused us to re-examine the best way to communicate with people who, like us, way to communicate with people who, like us, are passionate about Aquaponics.

are passionate about Aquaponics.

While we enjoyed putting the first issue of the While we enjoyed putting the first issue of the magazine together, it was a heap of work and magazine together, it was a heap of work and it was expensive. Also, while your feedback it was expensive. Also, while your feedback indicated that you liked what we did with the indicated that you liked what we did with the magazine, we felt that we were still too remote magazine, we felt that we were still too remote from our readership.

from our readership.

The outcome of that deliberation, as you will The outcome of that deliberation, as you will have observed, is the Aquaponics HQ web have observed, is the Aquaponics HQ web site.

site.

To promote greater interactivity, we installed To promote greater interactivity, we installed the Aquaponics HQ Forum to serve as a the Aquaponics HQ Forum to serve as a meeting place for those who want to discuss, meeting place for those who want to discuss, to contribute and to learn.

to contribute and to learn.

The fact that you’re reading this ‘zine The fact that you’re reading this ‘zine evidences our ongoing commitment to the evidences our ongoing commitment to the production

production of of a a bi-monthly bi-monthly magazine. magazine. TheThe differences between Issue #1 and those that differences between Issue #1 and those that follow is that they will be a bit slimmer and follow is that they will be a bit slimmer and they will

they will be be FREE. FREE. Aquaponics HQ Aquaponics HQ membersmembers can access it through the Forum.

can access it through the Forum.

The Forum and the Practical Aquaponics The Forum and the Practical Aquaponics e-Zine are

Zine are just the just the beginning. beginning. Watch this Watch this spacespace and you’ll begin to understand why this web and you’ll begin to understand why this web site

site is is called Aquaponics called Aquaponics HQ.HQ.

Murray H and Gary Donaldson

Running Your System

Using Timers

The flood and drain cycles in Aquaponics The flood and drain cycles in Aquaponics systems are controlled by electric timers, float systems are controlled by electric timers, float switches, auto-syphons or a combination of switches, auto-syphons or a combination of these.

these.

The simplest control systems (in terms of set The simplest control systems (in terms of set up) are ti

up) are timers. mers. Timers are Timers are of two main of two main types:types:

•

• Electric – adjustable in increments of 15Electric – adjustable in increments of 15

minutes minutes

•

• Electronic – adjustable in increments ofElectronic – adjustable in increments of

minutes – usually programmed to provide minutes – usually programmed to provide six on/off cycles.

six on/off cycles.

These commonly available timers can be These commonly available timers can be purchased in supermarkets and hardware purchased in supermarkets and hardware stores.

stores. I run I run a small a small flood aflood and drand drain gravein gravell grow bed which is fed by a 20w submersible grow bed which is fed by a 20w submersible pump on a timer.

pump on a timer.

The pumping cycle is on for about 15 minutes The pumping cycle is on for about 15 minutes and off for 45 minutes during which the grow and off for 45 minutes during which the grow bed

bed drains. drains. This This simple simple arrangement arrangement hashas operated for months now without problems. operated for months now without problems. Using a timer to act as a

Using a timer to act as a fail-safe when movingfail-safe when moving water around is a useful precaution.

water around is a useful precaution.

For example, if you are removing water from a For example, if you are removing water from a tank that contains fish, it makes sense to tank that contains fish, it makes sense to control the transfer of the water with a timer. control the transfer of the water with a timer. That way, if you forget that you are pumping, That way, if you forget that you are pumping, you will not empty the tank (and kill your fish). you will not empty the tank (and kill your fish).

Gary Donaldson

Timers

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What Should I Feed My Fish?

The three essential elements in any The three essential elements in any Aquaponics system are fish, plants and Aquaponics system are fish, plants and beneficial bacteria.

beneficial bacteria.

Your first task, once your fish tank is set up, is Your first task, once your fish tank is set up, is to “cycle” you

to “cycle” your system. r system. The purposThe purpose of cyclinge of cycling is to ensure that your system is colonised by is to ensure that your system is colonised by beneficial bacteria so that ammonia can be beneficial bacteria so that ammonia can be converted to nitrites and then for the nitrites to converted to nitrites and then for the nitrites to be converted to nitrates (plant food).

be converted to nitrates (plant food). Once your fish tank is full,

Once your fish tank is full, start your pump andstart your pump and begin recirculating water from your tank begin recirculating water from your tank through your grow beds and back to the tank. through your grow beds and back to the tank. Next, you add a source of nitrogen to the tank. Next, you add a source of nitrogen to the tank. Some people use live fish to cycle their Some people use live fish to cycle their systems.

systems. This This is is a a questionablquestionable e practicepractice because it puts the fish at risk.

because it puts the fish at risk. I prefer Nitrogen Dosing.

I prefer Nitrogen Dosing.

A nitrogen source like fish food, cooked or A nitrogen source like fish food, cooked or uncooked prawns or pure ammonia – is added uncooked prawns or pure ammonia – is added to the fish tank.

to the fish tank.

Ammonia levels will begin to rise and Ammonia levels will begin to rise and colonisation of Nitrosomonas bacteria (which colonisation of Nitrosomonas bacteria (which are naturally present in the air and water) will are naturally present in the air and water) will start to occur.

start to occur.

Bacteria numbers will increase to the point Bacteria numbers will increase to the point where the ammonia begins to convert to where the ammonia begins to convert to nitrite.

nitrite. The preseThe presence of nnce of nitrite in yitrite in your systemour system will encourage the colonisation of a second will encourage the colonisation of a second group of bacteria (known as Nitrobacter) and group of bacteria (known as Nitrobacter) and these will begin the conversion of nitrites to these will begin the conversion of nitrites to nitrates.

nitrates.

After you’ve added the nitrogen source to the After you’ve added the nitrogen source to the fish tank, commence daily water tests.

fish tank, commence daily water tests.

Once your system has registered ammonia Once your system has registered ammonia and nitrite readings of at least 5ppm and then and nitrite readings of at least 5ppm and then returned to ZERO, it is cycling.

returned to ZERO, it is cycling. How quickly your system cycles will

How quickly your system cycles will depend ondepend on a number of factors including water a number of factors including water temperature, bio-filter size, media type and temperature, bio-filter size, media type and water vo

water volume. lume. It could It could happen happen with a with a couplecouple of weeks if you take a diligent approach or it of weeks if you take a diligent approach or it could take considerably longer in more could take considerably longer in more adverse circumstances.

adverse circumstances. It is now time to

It is now time to add some fish.add some fish. Continue

Continue to closely to closely monitor wamonitor water quality ter quality untiluntil you confirm continuous nitrate production and, you confirm continuous nitrate production and, If you haven’t already planted out your grow If you haven’t already planted out your grow

If you want to achieve optimum growth for your If you want to achieve optimum growth for your fish, you should feed them a pelletised ration fish, you should feed them a pelletised ration that has been formulated for that particular that has been formulated for that particular species.

species. You can You can buy natibuy native fish ve fish pellets fropellets fromm feed stores.

feed stores.

Fish pellets come in a range of sizes to suit Fish pellets come in a range of sizes to suit the size

the size of fish of fish you are you are feeding. feeding. Some pelletsSome pellets will be made to float (while others will sink will be made to float (while others will sink quite quickly) to suit the feeding habits of quite quickly) to suit the feeding habits of particular species.

particular species.

beds, you can do so now. beds, you can do so now.

The presence of detectable levels of ammonia The presence of detectable levels of ammonia in your system from this point on suggests a in your system from this point on suggests a problem and should be addressed quickly. problem and should be addressed quickly.

Gary Donaldson

My Grow Beds and Fish Tank

are set up….what do I do now?

If you would prefer a more natural diet, and If you would prefer a more natural diet, and you are prepared to accept slower growth you are prepared to accept slower growth rates, you may be able to supplement your rates, you may be able to supplement your pellets with

pellets with duckweed oduckweed or Azolla. r Azolla. You can alsoYou can also feed worms, soldier fly larvae, mealworms or feed worms, soldier fly larvae, mealworms or other live food.

other live food.

How much you feed your fish is probably of How much you feed your fish is probably of equal importance to what you feed them.

equal importance to what you feed them.

About 3% of the total weight of fish per day is About 3% of the total weight of fish per day is a useful gu

a useful guide. ide. For exampleFor example, if your fish w, if your fish weigheigh about 200 grams each, and you have 100 of about 200 grams each, and you have 100 of them, you have about 20kg of fish in your t them, you have about 20kg of fish in your tank.ank. You would then feed 600 grams per day.

You would then feed 600 grams per day.

While you don’t have to be too precise, if your While you don’t have to be too precise, if your fish receive too little feed, they’ll take longer to fish receive too little feed, they’ll take longer to grow out.

grow out.

If they receive too much, it will remain in the If they receive too much, it will remain in the water and will contribute to poor water quality. water and will contribute to poor water quality. Some species of fish may also develop too Some species of fish may also develop too much body fat as a consequence of much body fat as a consequence of overfeeding.

overfeeding.

Pelletised fish food comes in a variety of sizes. Pelletised fish food comes in a variety of sizes.

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Because fish come in different sizes from tiny Because fish come in different sizes from tiny fingerlings to big ones, fish numbers are pretty fingerlings to big ones, fish numbers are pretty meaningless when it comes to deciding of the meaningless when it comes to deciding of the capacity of an Aquaponics system.

capacity of an Aquaponics system.

A much more accurate standard is kilograms A much more accurate standard is kilograms of fish per 100 litres.

of fish per 100 litres.

The weight of fish that can be kept in an The weight of fish that can be kept in an Aquaponics tank will be determined by factors Aquaponics tank will be determined by factors like:

like:

•

• The size of your tankThe size of your tank •

• The size of the fishThe size of the fish •

• The species of fishThe species of fish •

• The Dissolved Oxygen levels in the water.The Dissolved Oxygen levels in the water. •

• The bio-filtration capacity of your systemThe bio-filtration capacity of your system •

• The level of risk that you wish to The level of risk that you wish to assumeassume

Theoretically, the amount of fish that can be Theoretically, the amount of fish that can be kept in any system is limited only its ability to kept in any system is limited only its ability to convert ammonia and nitrites to nitrates convert ammonia and nitrites to nitrates (bio-filtration) and to maintain appropriate levels of filtration) and to maintain appropriate levels of oxygen in the water.

oxygen in the water.

For practical purposes, however, the level of For practical purposes, however, the level of risk is propo

risk is proportionate to the rtionate to the stocking rate. stocking rate. WhatWhat this means is that, if you are just managing to this means is that, if you are just managing to stay ahead of the requirement for ammonia/ stay ahead of the requirement for ammonia/ You can also adjust your feeding schedule to You can also adjust your feeding schedule to reflect your

reflect your need for nneed for nitrates. itrates. If your planIf your plants arets are growing slowly, gradually ramp up your growing slowly, gradually ramp up your feeding.

feeding.

Initially, this creates more ammonia, then Initially, this creates more ammonia, then nitrites and

nitrites and eventually eventually more nitratemore nitrates. s. You canYou can then reconcile your feeding with the

then reconcile your feeding with the capacity ofcapacity of your plants to absorb the

your plants to absorb the extra nutrients.extra nutrients.

Of course, all of this assumes that your tank is Of course, all of this assumes that your tank is at optimum

at optimum temperature. temperature. If the wateIf the water is coldr is colderer than optimum, you can expect that the fish will than optimum, you can expect that the fish will eat much less.

eat much less.

It’s also best to spread the daily ration across It’s also best to spread the daily ration across several smaller feeds rather than one large several smaller feeds rather than one large one.

one.

Remember, uneaten food eventually becomes Remember, uneaten food eventually becomes ammonia.

ammonia. If you see If you see food accumufood accumulating on lating on thethe bottom of your fish tank, stop feeding for a day bottom of your fish tank, stop feeding for a day or two.

or two. Withholding Withholding feed for feed for a day eva day every nowery now and then will probably do more good than and then will probably do more good than harm.

harm.

Gary Donaldson

nitrate removal and dissolved oxygen in the nitrate removal and dissolved oxygen in the system, you will have very little margin for system, you will have very little margin for error or mishap.

error or mishap.

If your stocking rates are high, you will need to If your stocking rates are high, you will need to have warning or back-up (preferably both) have warning or back-up (preferably both) systems in place if you are to avoid injuring or systems in place if you are to avoid injuring or killing fish in the event of a power or killing fish in the event of a power or equipment failure.

equipment failure.

Conversely, if you have a very low stocking Conversely, if you have a very low stocking rate you may not have sufficient nitrates to rate you may not have sufficient nitrates to feed

feed your your plants. plants. Aquaponics is Aquaponics is a a balancingbalancing act that must be managed effectively if useful act that must be managed effectively if useful productivity is to be achieved.

productivity is to be achieved.

Gary Donaldson

How Many Fish Can I

Keep In My Tank?

Why I Chose Silver Perch for

my Aquaponic System.

The short answer is, that this species is

The short answer is, that this species is prettypretty tough and they are easy to get.

tough and they are easy to get.

Many people begin by wanting to keep Many people begin by wanting to keep Barramundi in their aquaponics system.

Barramundi in their aquaponics system.

Barramundi are well known as a good eating Barramundi are well known as a good eating fish. In that respect, Silver Perch are not fish. In that respect, Silver Perch are not eveneven close in terms of

close in terms of their public profile.their public profile.

I have dozens of visitors to see my system I have dozens of visitors to see my system every month and very few of them have even every month and very few of them have even heard of Silver Perch.

heard of Silver Perch.

Silver Perch are far easier to keep than Silver Perch are far easier to keep than Barramundi.

Barramundi.

Silver Perch are very tolerant of lower water Silver Perch are very tolerant of lower water temperatures that typically occur in the winter temperatures that typically occur in the winter months.

months.

My Silvers are still eating well and are moving My Silvers are still eating well and are moving briskly around in the tank when the water briskly around in the tank when the water temperature gets down to 15 deg C.

temperature gets down to 15 deg C.

Barramundi would be starting to slow down at Barramundi would be starting to slow down at 15 deg C and it would not be good to have 15 deg C and it would not be good to have the water temperature much lower that that the water temperature much lower that that for them.

for them.

Silver Perch are not as likely to succumb to Silver Perch are not as likely to succumb to such diseases as white spot and fungal such diseases as white spot and fungal attack.

attack.

Silver Perch tend not to bother smaller fish Silver Perch tend not to bother smaller fish co-habiting

co-habiting in thin the tane tank wk with theith them. m. I haveI have large Silvers (1.5kg) and Silver fingerlings large Silvers (1.5kg) and Silver fingerlings sharing the same tank and the big fish do not sharing the same tank and the big fish do not bother the smaller ones.

bother the smaller ones.

Continued on Page 5

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Duckweed is one of the best-kept secrets of Duckweed is one of the best-kept secrets of Aquaponics.

Aquaponics.

It is a high quality feedstuff that can be It is a high quality feedstuff that can be produced in useful quantities at little cost and produced in useful quantities at little cost and with little

with little effort. effort. Of equaOf equal interest l interest (particularl(particularlyy in an Aquaponics context) is its ability to in an Aquaponics context) is its ability to remove nutrients from water.

remove nutrients from water.

We began growing duckweed in 2004. We began growing duckweed in 2004. Initially, we used it to supplement the Initially, we used it to supplement the pelletised rations that we fed to our Japanese pelletised rations that we fed to our Japanese quail.

quail. In more reIn more recent times, cent times, it has beit has become ancome an important part of the diet that we provide to important part of the diet that we provide to our Jade Perch.

our Jade Perch.

Duckweed

…fast food for fish

semi-shade or somewhe

semi-shade or somewhere that you are re that you are able toable to shelter them from the worst of the summer shelter them from the worst of the summer heat.

heat.

You should aim for complete and dense cover You should aim for complete and dense cover of duckweed (within the range 0.6kg/m of duckweed (within the range 0.6kg/m22 – – 1.2kg/m

1.2kg/m22) for backyard farming purposes.) for backyard farming purposes. Much below this and algal blooms will be an Much below this and algal blooms will be an issue and much above it will cause it to issue and much above it will cause it to self-mulch.

mulch. Wind Wind or or fast-flowing fast-flowing water water will will alsoalso cause diminished production due to cause diminished production due to self-mulching.

mulching.

While a variety of organic materials can be While a variety of organic materials can be used to supply nutrients for duckweed, the used to supply nutrients for duckweed, the logical source for Aquaponicists is their fish logical source for Aquaponicists is their fish tanks. Of particular importance to tanks. Of particular importance to aquaponicists, is the plant’s nutritional aquaponicists, is the plant’s nutritional preference for nitrogen in the form of preference for nitrogen in the form of ammonia.

ammonia.

While it is not essential, recirculating water While it is not essential, recirculating water from yo

from your fish ur fish tank is tank is desirable. desirable. Aside Aside fromfrom saving you the effort of bucketing water from saving you the effort of bucketing water from your fish tank, recirculating the water will your fish tank, recirculating the water will ensure that the nutrient levels in your ensure that the nutrient levels in your duckweed pond remain at a consistent level. duckweed pond remain at a consistent level. This arrangement will also help to remove any This arrangement will also help to remove any traces of ammonia that may be present in the traces of ammonia that may be present in the tank water.

tank water.

Duckweed is capable of rapid growth in water Duckweed is capable of rapid growth in water containing just trace elements of nutrients. containing just trace elements of nutrients. Interestingly, we almost killed off a batch of Interestingly, we almost killed off a batch of duckweed through overdosing it with poultry duckweed through overdosing it with poultry manure.

manure.

Temperature and sunlight are more important Temperature and sunlight are more important growth parameters than nutrient growth parameters than nutrient concentrations.

concentrations.

Duckweed grows across a wide temperature Duckweed grows across a wide temperature range – between 6

range – between 6ooC and 33C and 33ooC – but we’veC – but we’ve determined that it grows best in a range of determined that it grows best in a range of 18

18ooC to 24C to 24ooC. C. We We know know that that growth growth slowsslows progressively up to 30

progressively up to 30ooC and the plant beginsC and the plant begins to die off quickly at around 33

to die off quickly at around 33ooC.C.

While it will live in pH 5 to 9, the optimum pH While it will live in pH 5 to 9, the optimum pH for growing duckweed is in the range of pH 6.5 for growing duckweed is in the range of pH 6.5 to 7.5 – also the preferred range for to 7.5 – also the preferred range for aquaponic

aquaponics s systems.systems.

Duckweed

Duckweed - - among among the sthe smallest mallest flowering flowering plants plants inin the World

the World - - and an and an excellent naturexcellent natural food al food for fish.for fish.

In the right conditions, this tiny plant can In the right conditions, this tiny plant can double its mass every 24 – 48 hours.

double its mass every 24 – 48 hours.

Its explosive growth rate enables you to Its explosive growth rate enables you to harvest and feed fresh duckweed on a daily harvest and feed fresh duckweed on a daily basis.

basis.

At 35% to 40%, it has a higher protein level At 35% to 40%, it has a higher protein level than Soya beans and higher concentrations of than Soya beans and higher concentrations of the essential amino acids, lysine and the essential amino acids, lysine and methionine than most plant

methionine than most plant proteins.proteins.

The other great news is that growing The other great news is that growing duckweed

duckweed is is easy easy - - particularly particularly in in the the smallsmall ponds and tanks favoured by backyard food ponds and tanks favoured by backyard food producers.

producers.

You can purchase your initial stocks

You can purchase your initial stocks from mostfrom most aquarium supply shops.

aquarium supply shops.

You can use any open tank, large tub or You can use any open tank, large tub or in-ground

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Feeding out duckweed is as simple as Feeding out duckweed is as simple as dragging a kitchen sieve through the dragging a kitchen sieve through the duckweed tank and placing it into your fish duckweed tank and placing it into your fish tank.

tank.

To avoid the duckweed from being pumped To avoid the duckweed from being pumped out of the tank, we made up an inexpensive out of the tank, we made up an inexpensive duckweed feeder from a bucket with the duckweed feeder from a bucket with the bottom remo

bottom removed. ved. The buckeThe bucket is sut is suspended spended inin the water and the duckweed is placed into the the water and the duckweed is placed into the bucket.

bucket. This aThis arrangement rrangement allows allows the fish the fish toto access the duckweed without distributing it access the duckweed without distributing it throughout the tank.

throughout the tank.

Surplus duckweed can easily be dried and Surplus duckweed can easily be dried and stored

stored for for later later use. use. When When drying drying smallsmall quantities, we allow the duckweed to drain in quantities, we allow the duckweed to drain in aa kitchen sieve and then spread it thinly over kitchen sieve and then spread it thinly over several thicknesses of newspaper or kitchen several thicknesses of newspaper or kitchen towel.

towel. Turn it over Turn it over several timeseveral times each das each day fory for two or three d

two or three days. ays. Store it in an Store it in an airtight plasticairtight plastic container.

container.

Freezing is actually our preferred duckweed Freezing is actually our preferred duckweed storage me

storage method. thod. We simply We simply gather up gather up the tinythe tiny plants in a small kitchen sieve and squeeze plants in a small kitchen sieve and squeeze the excess water out of them before arranging the excess water out of them before arranging the mass in a

the mass in a shallow plastic container.shallow plastic container.

Our first challenge was to learn how to grow Our first challenge was to learn how to grow duckweed in consistent,

duckweed in consistent, predictable quantities.predictable quantities. Our current focus is on the full integration of Our current focus is on the full integration of the plant

the plant into an into an aquaponics system. aquaponics system. We wantWe want to be able to grow duckweed to remove to be able to grow duckweed to remove nutrients, feed fish and other small livestock nutrients, feed fish and other small livestock and to conserve water through reduced and to conserve water through reduced evaporation.

evaporation. Duckweed is a

Duckweed is a must have must have _{for the backyard}_{for the backyard}

Aquaponicist. Aquaponicist.

Bio-security Warning Bio-security Warning

Duckweed (and all other aquatic organisms in Duckweed (and all other aquatic organisms in an Aquaponics system) should not be allowed an Aquaponics system) should not be allowed to make their way back into any natural to make their way back into any natural watercourse.

watercourse. Plants Plants from from an an aquaponicaquaponicss system that are introduced into the wild may be system that are introduced into the wild may be carrying disease organisms that can be carrying disease organisms that can be transmitted to other plants, animals or fish. transmitted to other plants, animals or fish. Cover duckweed tanks with mesh to prevent Cover duckweed tanks with mesh to prevent birds from drinking from the tank and birds from drinking from the tank and transferring the duckweed on their feathers. transferring the duckweed on their feathers.

Gary Donaldson

Surplus duckweed can be frozen and fed out during Surplus duckweed can be frozen and fed out during colder weather when growth may slow down.

colder weather when growth may slow down.

After freezing, we turn it out of the plastic After freezing, we turn it out of the plastic mould and place the duckweed biscuit into a mould and place the duckweed biscuit into a large

large storage storage container. container. Whenever Whenever we newe needed duckweed for our fish, we select

duckweed for our fish, we select what we needwhat we need from the storage container in the freezer and from the storage container in the freezer and float it on the surface of the

float it on the surface of the fish tank.fish tank.

To summarise, duckweed is a high quality To summarise, duckweed is a high quality source of plant protein that grows quickly, source of plant protein that grows quickly, costs virtually nothing to produce and requires costs virtually nothing to produce and requires little

little labour. labour. It offers It offers the athe added dded benefit benefit ofof being able to remove nutrients from water. being able to remove nutrients from water.

Why I chose Silver Perch….cont’d

This

This is a is a useful useful trait ftrait for smor small all systems. systems. ItIt allows you to have Silver Perch of various allows you to have Silver Perch of various ages growing out in the one tank, thus ages growing out in the one tank, thus providing a steady stream of ready-to-harvest providing a steady stream of ready-to-harvest fish for the table.

fish for the table.

I have just harvested a good number of my I have just harvested a good number of my bigger fish and added 200 more fingerlings to bigger fish and added 200 more fingerlings to the sa

the same tankme tank. . In aroIn around 1und 12 month2 months I s I willwill have the next crop coming along.

have the next crop coming along.

Silver Perch are readily available from fish Silver Perch are readily available from fish hatcheries

hatcheries right right across across Australia. Australia. In In mostmost cases, it is possible to obtain small quantities cases, it is possible to obtain small quantities for as little as one dollar per fingerling.

for as little as one dollar per fingerling.

Silver Perch represent good value and are Silver Perch represent good value and are easy to manage for the home hobby system easy to manage for the home hobby system and the commercial enterprise alike.

and the commercial enterprise alike.

Murray H…

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How to Build

a Grow Bed Stand.

How to make a very strong and attractive grow How to make a very strong and attractive grow bed stand from easily obtainable materials at a bed stand from easily obtainable materials at a economical cost.

economical cost.

This grow bed stand will support a standard grow This grow bed stand will support a standard grow bed with the base at a height of 450mm above bed with the base at a height of 450mm above ground.

ground.

Materials needed are: Materials needed are:

•

• 8 standard concrete blocks8 standard concrete blocks •

• 3 x 50mm x 2400mm pine/hardwood sleepers.3 x 50mm x 2400mm pine/hardwood sleepers.

Tools needed are: Tools needed are:

•

• A square nosed shovel.A square nosed shovel. •

• Long spirit level.Long spirit level. •

• Hand or power saw.Hand or power saw. •

• Set square.Set square. •

• Tape measure and pencil.Tape measure and pencil.

The cost of the

The cost of the materials will vary slightly from townmaterials will vary slightly from town to town. In Brisbane, at my local landscape to town. In Brisbane, at my local landscape supplies place, the concrete blocks cost $3.50 supplies place, the concrete blocks cost $3.50 eacheach and the sleepers were $15.00 each for a total tab of and the sleepers were $15.00 each for a total tab of $73.00.

$73.00. Shopping Shopping around around may may produce produce a a betterbetter price.

price.

Confirm the location for the

Confirm the location for the grow bed. grow bed. You need You need toto get this right because, once it is

get this right because, once it is filled, the grow bedfilled, the grow bed will be far too heavy to move.

will be far too heavy to move. Getting the

Getting the grow bed grow bed level is level is the next the next priority. priority. ItIt helps if you have a level piece of ground to start helps if you have a level piece of ground to start with.

with. I determined I determined that there that there was about was about 25mm fall25mm fall from one end of the space from one end of the space to the other.

to the other.

By placing one block By placing one block down at each end and down at each end and using one of the sleepers using one of the sleepers on it’s edge and using the on it’s edge and using the spirit level you will be able spirit level you will be able see if it is level.

see if it is level.

Gradually scrape away Gradually scrape away small amounts of dirt small amounts of dirt where required until it is where required until it is level both ways.

level both ways. This phase of the

This phase of the construction may take some time,construction may take some time, but be patient and

but be patient and spend the time to spend the time to get it right.

get it right.

In positioning the In positioning the blocks make sure blocks make sure you leave enough you leave enough room at one end for room at one end for the drain outlet from the drain outlet from the grow bed.

the grow bed.

Once the blocks are Once the blocks are in position and level, in position and level, fill them with some fill them with some Start by scraping the dirt Start by scraping the dirt back at the high end first back at the high end first to get a level site.

to get a level site.

of the same gravel that you will use in the grow of the same gravel that you will use in the grow bed.

bed.

This helps to stabilise the blocks a

This helps to stabilise the blocks a little and has thelittle and has the effect of helping spread the load by transferring the effect of helping spread the load by transferring the load over the whole footprint of the blocks.

load over the whole footprint of the blocks.

Filling the blocks with concrete will make the Filling the blocks with concrete will make the structure stronger.

structure stronger. Depending Depending on on the the nature nature ofof your soil, you may even decide to lay concrete your soil, you may even decide to lay concrete footings.

footings.

Once this is finished, lay

Once this is finished, lay the sleepers in place.the sleepers in place. Level ends at one end and trim the other end using Level ends at one end and trim the other end using your circular saw or hand saw to a length to suit your circular saw or hand saw to a length to suit thethe grow bed.

grow bed.

Notice the middle sleeper has been left short to Notice the middle sleeper has been left short to allow for the drain pipe to come out for the return allow for the drain pipe to come out for the return line.

line. Now put the Now put the grow bed grow bed in place ready in place ready to loadto load the gravel and fit the

the gravel and fit the pipe work.pipe work. How easy is that?