Joey

Joey's Hybrid Gravel grow bed/Floating raft system

157 posts in this topic

The weather has warmed up and the silver perch seem to be more active and are eating more. The new floating raft grow beds have been filled with lettuce, broccoli, silver beet and basil in preparation for the anticipated increase in nutrients.

This system has been designed to grow with the fish tank dug into the ground acting as a sump. I have found that since the new filtration equipment and floating raft grow beds have been added there is an extra 250 litres of water in suspension in the system. This has reduced the low water level of the fish tank to approx 1000 liters.

I cannot top up the tank as in the event of a stoppage this suspended water could return and over flow the fish tank. The system is still evolving and with the next increase in grow beds I will need to add an additional fish tank with the old tank remaining as a sump/fingerling tank.

Attached is a flow diagram of how the system is currently set up.

Joey

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Nice. Any photo's? I like the idea of combining growbeds for nitrification and rafts for cheapness and the stability that comes from having more water.

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Hello SVC there are some photos on my previous post of the system as it was then. You can see these by pasting this link into your browser.

http://www.aquaponicshq.com/forums/showthread.php/3681-Update-from-Joey

I added the rafts as I believe things may grow quicker as well as adding additional water into the system for added stability.

As raft systems depend on clean filtered water, I added two additional stages of filtration into the loop.

I hope it works.

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Hi Joey,

Good looking design.

Both of your growing systems will benefit from the use of the settling tank. It will trap much of the solid waste. The bathtub full of gravel will help to keep your raft tanks clean, too.

Are you planning to make your own grow beds/tanks or do intend to buy something off the shelf?

Gary

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Hello Gary

My system is entirely home made or home sourced, the settlement tank came from Bunnings, the 1650 litre Fish Tank is a drinking trough from OPS Country Tanks cost about $350.00 and is food grade.

The floating raft grow beds are already up and running and fully planted out with seedlings.

The settlement tank is working with waste already building up on the bottom as well as on the internal pipes. I am thinking of throwing in a few more plastic pipe offcuts into the tank to aid this process. It is mounted on a wooden platform outside the polly tunnel with a 40mm ball valve fitted to enable the sludge to be drained off.

The gravel grow bed and the two floating raft grow beds are home made. The legs were made from left over steel offcuts obtained free, the sides were made from F7 treated pine planks that were left over in my shed from a project that never went ahead. The laminex lining was bought for $10.00 a sheet on ebay. The bottom is 18mm form play re-enforced with timber bracing underneath. The dimensions are 2400mm x 1200mm x 300mm. The floating rafts are made from polystyrene with holes melted into them with a suitable heated piece of pipe.

Joey

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Hi Joey,

That's one amazing grow bed.......and the area is perfect. I don't know why there are not more 8' x 4' grow beds around. They are a perfect size.....with the centre being easily accessible from both sides.

Your use of Laminex as a waterproof surface is also very innovative........I've never heard of it being used before.

Excellent job, mate. Keep us posted on how this is all working for you.

How deep is your fish tank?

Gary

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Hello Gary for

These troughs are 650mm deep, however the bottom is curved so when the soil is sloped towards the centre the trough would be 750mm deep in the centre.

I intend to expand the system over the next few weeks to include some trout so I intend to visit the Ballarat hatchery. Initially I will add a separate fingerling tank into my existing system then build a new system housed in my shed to try and get them through the summer. I will build a bio filter for this system as well as grow beds with the option of shutting down the grow beds during hot periods. Any advice on effective bio filters would be appriciated.

While looking for another trough, I found some factory seconds and bought enough to make another system. All food grade plastic. See photos attached.

Regards

Joey

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Hi Joey,

Great photos......and excellent plant growth.

Congratulations on the tanks seconds. This sort of opportunism can knock hundreds of dollars of the cost of system without necessarily compromising its functionality.

A trickle bio-filter is easy to make and operate. They are not only good for bio-filtration but are also excellent for aeration.

Buying trout going into summer is a bold move. You are going to have to do something out of the ordinary to keep them alive during the hot times.

How big do you expect them to be when you get them? Have you already committed to their purchase? Would silver perch not be a better choice given the approach of summer?

Give me some information about the size of the fish tank to which you will attach the bio-filter......and how many fish you've ordered.......and I'll help you to design suitable trickling filters.

One idea might be to fit a small fan to your bio-filter......so that it creates an updraught of air through the bio-filter media. It would act like an evaporative cooler.

I'd also have plenty of ice in the freezer for those days when you just have to get the temperature down as fast as possible......anyway you can.

Gary

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Than Garry

The Tank will be the 1650 litre trough I just bought, installed in my shed to keep it out of the weather. The 3 grow beds will be mounted outside with a 690 litre sump buried in the ground underneath them.

Your idea of building a trickling bio filter especially if I can integrate a fan is a great idea and I would also house this in the shed. I would like to be able to isolate the grow beds on hot days leaving just the bio filter in the circuit.

I will take your advice in having a supply of ice in the deep freezer in case of emergencies.

I have been advised by the Ballarat hatchery that small trout fingerlings are just now becoming available, I am thinking about buying about 50 to 100

If I find that I can get small trout fingerlings through the summer I would switch to trout for it's eating qualities and better growth rates.

Regards

Joey

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Hi Joey,

Are you sure you're going to be able to maintain your water temperature below 22 degrees C? Ideally, the water temperature should be around 18 degrees C.

Can you measure the height of your fish tank and I'll endeavour to design the trickle filter set up to suit.

Gary

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Very impressive looking design & system Joey, congrat's.

Good luck with the Trout in Melbourne over summer, it was too hot for me to get mine through last year.

Ended up pulling them out to eat (lost a couple due to the temps).

Your Tommie plants are far more advanced than mine, mine have not set any fruit yet.

Cheers,

Shane.

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Thanks Garry and Shane

Garry the new system for the trout has a fish tank of 1650 litres 1.8 metres round and 650 mill deep. There is a bow in the bottom which will allow me to slope the bottom towards the centre making it 750 mil deep at the centre, this will also assist solids to move to the centre of the tank. It will be installed in the shed and as we are including a sump the fish tank will always be full. The sump is 690 litres and will be dug into the ground underneath the grow beds outside. The grow beds are 520 litres each. The trickling Bio filter you suggested and swirl filter will be installed in the shed. I will be looking forward to details on the bio filter which includes evaporative cooling tower features.

As the trout are very small I am hoping that they may survive the odd times when water temperatures rise to 27 degrees assisted with a good air supply. If I don't try I won't know. Shane as for the tomatoes they are currently growing in an autopot using hydroponic nutrient in a unheated hot house so we are not comparing apples with apples. When my system matures and produces enough nutrients I will put fish water into the autopot system. I currently have 60 small silver perch in the system and most of the vegetables with the exception of the snow peas are growing very slowly.

Regards

Rudy

Edited by Joey
cut of when entering before (see edit history)

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Early last December I decided to bite the bullit and travelled to Ballarat to purchase 50 trout fingerlings. They were a bargain at only 80 cents each. On the first night I lost 6 of them as they jumped out of the fingerling tank, which was not yet covered. The rest are doing fine so far. I made a mistake in how high these little things can jump.

They are kept in a CHOP 750 litre fingerling tank which has it's own filter made out of a rubbish bin filled with shells. It also shares the water and filtration from the main system, however it can be easily isolated to function alone if required. I am planning to build a new system to house the trout once they get larger.

In an attempt to be able to cool the water I have built a tower out of a sheet corflute found on the side of the road. I rolled it up to size so that an electric fan can be neatly inserted at the top. It faces down and blows towards the water. A sprinkler sprays water inside which run down the walls until it hits the water. I tried misting jets however my pump does not have enough pressure to run them.

As the hot weather has not arrived yet the real test for this is still to come. So far I have had no need to run the fan as the water has been constantly below 20 degrees.

My silver perch in the other tank seem to be in hiding and are eating very little. So it is great to have some fish that swim up and eat eagerly. They have nearly doubled in size in just four weeks and will soon be bigger than my 6 month old silver perch.

The attached photo shows the cooling tower sitting on top of the tank along with the rubbish bin filter both of these run straight back into the tank.

Joey

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Hello Gary

So far I have found that the cooling tower does not have much of an effect on water temperature. I think the main benefit is increased aeration by water falling from a height of 1 meter into the water. When the fan and water is running the temperature of the air hitting the water is about 22 degrees while the external air temperature is 28. My air pump sucks up this cooler air. As far as cooling the water I believe the effect is minimal. The hottest my water has been this year is 23 degrees it is currently 21 degrees. The trout so far appear healthy and are growing well, although some seem to be growing quicker than others.

Rudy

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Hi Rudy,

You may get more of a cooling effect if you create a packed column filled with lightweight media and allow the water to percolate down through the media while drawing air up through the media at the same time. You'll get good nitrification, great aeration and possibly even some evaporative cooling, too.

I use oyster shells in my trickling bio-filters. Aside from being free, they don't block up even when you put solids through them. Of course, if you remove the solids before the water goes to your trickle tower, you won't have a clogging problem anyway.

Given that we're still very much in warmer times, I'd keep some blocks of ice handy in the freezer.....just in case things get nasty for your trout.

Gary

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Two weeks ago I added a 350 litre fingerling tank into my existing system between the DWC grow beds and the Sump/Fish tank. It has been stocked with 50 silver perch fingerlings from Glenwaters Native fish farm. They have settled in well and are feeding like crazy.

The trout fingerlings purchased last December from Ballarat are also doing well and showing amazing growth. Due to the coolest summer in my memory the water has not been higher than 24 degrees and is currently stable at 22 degrees, however the ice I put away for emergencies is still in the freezer. I am not running the fan in the cooling tower. It is just acting as a trickling bio filter with water cascading through a rolled up piece of shade cloth.

The older batch of silver perch are also feeding well and showing good growth.However I find them nearly impossible to catch in that 1750 litre tank below the gravel grow bed.

I am currently building a new home for my trout in the garage. It will consist of a 1750 drinking trough fish tank, a 350 litre swirl filter, a 350 litre settlement tank, a 350 litre trickling bio filter and a 700 litre sump tank.

I am planning to run this as a stand alone system with the option of interconnection to the older system.

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Hi Rudy,

It is just acting as a trickling bio filter with water cascading through a rolled up piece of shade cloth.

How's that working? Are you experiencing any clogging with the shade cloth?

Gary

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Hello Gary

I have removed the cooling tower as it was making it difficult to clean the tank underneath. The shade cloth has been relocated into my settlement tank where I hope it can help catch solids. I have not had many problems with water temperatures with 24 degrees being the hottest I have had, currently the water is steady between 18 and 20 degrees. The trout I purchased in December are still doing fine and growing well. They are currently about 125mm long and were about 50mm when I brought them home. The new batch of silver perch from Glen Waters are eating well but are still very small between 60mm and 70mm.

Things have been moving slowly with the new home for the Trout as I have been working on a new poly tunnel for my wife's chilly collection. I have also constructed a wicking bed made from left over colour bond sheeting, along the lines of those constructed by Crusty.

Will post some photos later.

Rudy

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Hi Gary

What is happening for me is that the system is currently maintaining good water quality and is keeping healthy fish, however plant growth has been very slow.

The fish load is currently as follows:

. 57 Silver perch in July 2010 (size 100mm to 125mm)

. 30 Trout purchased in December 2010 (size 100 to 125mm)

. 50 Silver perch purchased late January 2011. (size 60mm to 70mm)

The system currently consists of the following components:

. 1 1750 litre Sump tank. (Home for the original 57 silver perch)

. 1 800 litre River Pebble grow bed

. 2 800 Litre DWC grow beds

. 1 300 Litre Settlement / Swirl Tank.

. 1 Bath Tub with gravel acting as a trickling bio filter.

. 1 690 Litre Chop tank (Home for the 30 Trout.)

. 1 375 Litre Chop tank (Home for the new 50 silver perch)

. 1 60 litre Rubbish bin Trickling Bio filter filled with sea shells above the trout tank.

. 2 3500 Litre per hour pumps (In the sump tank.)

. 1 2500 Litre per hour pump (Circulating water in the trout tank)

. 1 20 litres per minute air pump (Supplies air to sump tank and 690 Litre trout tank)

. 1 50 litres per minute air pump (Supplies air to DWC grow beds and the 375 Litre chop tank for Silver perch)

I have been dissapointed with the slow growth of the vegetables growing in the DWC beds and the small white aphids that have spoiled the produce.

The gravel grow bed has not had an aphid problem and produced Silver beet and Snow Peas. However even here the growth has

been slow.

So far my aquaponics system seems to be ok for growing fish, however it is our dirt garden that has been keeping us supplied with vegetables.

Rudy

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Hi All

I bought an underwater camera from Teds Camera store today $59.00 used it to make a small video of my Silver Perch fingerling tank.

Rudy

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Hi Rudy,

I love the underwater shots of the fish. Capturing good images of the fish can be problematic at the best of times so taking the footage from within the fish tank seems like a great approach.

With reference to your previous post, aquaponics systems often take a while to mature so don't be too concerned about your poor plant growth at this stage. While a mature AP system won't require the addition of such things, you could add a bit of Seasol to your system to kick your plants along.

Are you mineralising the solids from your swirl tank and adding the nutrients back into the system? That will certainly help, too. Let me know if you need further advice on how to do this.

Taking the water from your aquaponics system to water your soil-based gardens allows you to achieve the core benefit of aquaponics - getting both fish and plants from the same amount of water that it would otherwise take to just grow the fish.

Gary

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I am currently building a new home for my trout in the garage. It will consist of a 1750 drinking trough fish tank, a 350 litre swirl filter, a 350 litre settlement tank, a 350 litre trickling bio filter and a 700 litre sump tank.

I am planning to run this as a stand alone system with the option of interconnection to the older system.

Hi Joey,

Did you end up completing your stand alone system in your garage?

Cheers,

Shane.

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Hi Shane

I have been very slow to complete this project. It is becoming more urgent as the trout in their 690 litre fingerling tank are eating like crazy and growing very fast. They need to be relocated very soon. My water temperature is now down to 12 degrees. The Silvers have slowed down on their eating however the trout certainly make up for that.

For the first time since I have had the system I am getting low levels of nitrate readings and my DWC lettuces are growing well.

I will post some photos later on today to show progress.

Regards

Joey

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