Backyard Aquaponics
A place to discuss aquaponics

Hi all, I finally managed to upload a photo so I can now commence my long awaited build thread.

First a brief intro!

A few years ago I used to throw all the waste water from my aquarium into the same spot in my garden. I noticed that everything in that area grew much faster and nicer than the rest of the garden.

A good few years on, different house different country and the invention of the Internet made me realise what had happened. I researched Google and thus found aquaponics.

I was instantly hooked and had to build a system. I wasn't however going to spend money and build a system and realise I'd got it all wrong and so began months of research, looking at other peoples problems and questions and only being satisfied once I believed I had a good basic knowledge of fish keeping, water chemistry, plant needs etc.

The next stage was to make a scale drawing of what I wanted to achieve........

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White spots on plant leaves and very very hard water could just mean it's winter!

You may have noticed that I opted for a pond and not a traditional CHOP system. The main reasons for this are because we have a reasonably nice garden and want to keep the plastic and pipes to a minimum for aesthetic purposes and also we don't want to kill and eat our own fish.

I understand that this reduces its efficiency but it suits our needs perfectly.

Once the drawing was done the calculations had to start.

Being AquaPONDics meant no pump in the fish tank (pond) as a blockage could spell disaster. This means all the water change had to be done by inflow and overflow.

The overflow flows into a separate pump tank situated 3cm below the pond.

The pond is filled via overflow from the collective sump tanks situated below each grow bed and the return is regulated by a flow valve as near as I can possibly regulate it to just more than the pump flow. (I'll explain why just more and not equal or less later!)

This meant lots of calculations

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White spots on plant leaves and very very hard water could just mean it's winter!

Next I started to build the components.....

Swirl filter.......

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White spots on plant leaves and very very hard water could just mean it's winter!

You can see the angle at which it has been placed. This is so solids collect in the bottom right fwd corner. I have placed a drain tap attached to a pipe which allows solids removal without stopping the system. Any amount of water drained off is replaced back into the swirl filter. (More on that later)

Since fitting the swirl filter I have added an overflow which bypasses the BIO filter and goes straight to the header tank just in case there is ever a blockage in the bio filter. Otherwise all the water from the swirl filter then passes through the BIO filter on the way to the header tank.

Header tank (prepared for future expansion to 4 grow beds)



What you don't see in this photo are the swirl filter overflow inlet and the BIO filter inlet.

The two inlets are situated slightly higher than the overflow outlet which is situated approximately 6cm above each of the four outlets.

You may notice later in the build that the colour has changed. That may have something to do with me knocking it off my grow bed and smashing it it's all new now though!

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White spots on plant leaves and very very hard water could just mean it's winter!

Its a big learning curve for a start get rid of those clear plastic containers they are not uv stabilised and they will also grow algi
Do it right first time

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If it/s free pick it up
If it isent broke dont fix it

In between the (new black UV stabilised) header tank and the swirl filter is a gray UV stabilised BIO filter.

FAF. I understand what you are saying about growing algie but I like to see through it when I brush the solids towards the drain hole, I find it a little easier. I will make a new one so I can swap it in the event of a problem. I made everything so that it just unscrews at the bulkheads in case of replacement.

The BIO filter has all the usual BIO media inside. Everything sits in a plastic shopping basket with a handle for easy removal. The basket sits on the inlet pipe which enters at the bottom and travels all around the base of the filter box. The pipe forms a closed circuit and water exits the pipe via holes drilled on the underside. These holes are positioned so the flow of the water doesn't allow build up in the corners or edges and forces the water up through the basket and media. Well, in theory at least. That said it seems to be doing ok so far.



Next up was making my pump tank and placing it in the ground



Being buried meant making a floating water level indicator so I can constantly monitor the level without having to remove anything.

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White spots on plant leaves and very very hard water could just mean it's winter!

After finishing the liftable cover I painted a scale on the indicator to make it easier to read the level.

It's a bit 'Rasta' but I like it.

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White spots on plant leaves and very very hard water could just mean it's winter!

The 'cuves'. IBC's? Arrived ang got cut and cleaned. I bought some wood for cladding and some posts for bearing the weight of the filled beds then got to work.



I cut some notches in the wooden frame




Next I built the first frame

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White spots on plant leaves and very very hard water could just mean it's winter!

After building the first bed I made the mistake of only giving a 'quick rince' to the clay ball media when in fact it needs a 'bloody good wash!' I had to clean out all the beds and sumps

I decided to cover the inside of the beds with black plastic to hide the white plastic IBCs because they weren't cut perfectly straight. Absorbs a bit extra heat and doesn't reflect as much light but hides the rough edges so swings and roundabouts I'm happy enough!

Next up was bed number 2 which had to be 2 cm higher than bed 1.

Floor levelled and channel cut to hide all the pipes below ground



The bed was built and the pipes added



Then everything was back filled to hide all the pipe work

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White spots on plant leaves and very very hard water could just mean it's winter!

Dont think I would ever bury pipe work again

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If it/s free pick it up
If it isent broke dont fix it

Here's a quick look at the beds being built. You can see I have used a thick post as a weight bearing frame.

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White spots on plant leaves and very very hard water could just mean it's winter!

At the moment I have only 2 grow beds made and operational with the possibility of expansion to four in the future. Each bed has/will have a connected sump. The return to the pond is from one sump and for that reason it is situated 2cm below the others. This allows for the possibility of all four grow beds emptying at the same time and not overflowing the sump. The fact one is lower means all the water naturally flows into it and it's the last to empty.

Next up was regulating the return flow to the pond. THIS IS VERY IMPORTANT TO GET RIGHT. it has to be regulated to as close as possible to the flow of the pump PLUS A LITTLE MORE. Here's why......

For ease of explanation let's say the pump pumps out 60L/min and you have a pump tank of 60L. In one minute it will be empty. If you have a return of 59L/min you will lose 1L/min and the pump tank will be empty in 1 hour.

The obvious thing to try and do is get the return exactly the same as the pump BUT...... When it rains the pond overflows into the pump tank, this raises the level of the water in the pump tank which means the head height of the pump is reduced. In turn this makes the pump more efficient and pump slightly more water. (See your pump head height chart) during warm periods you may experience evaporation which has the opposite effect and reduces the pump efficiency.

Its very difficult without (even with) precise measuring equipment to know the exact flow over an extended period and that is why you must regulate to the pump plus a little bit. Here's how I did it.

I connected a temporary pipe from the sump to the pump tank



Then I added TWO flow valves, one for stopping the water if and when necessary and the other for regulating the flow. Once this valve is regulated it doesn't need to be adjusted again. (It's fiddly to get right and takes time)



SO what happens because the water returns more than the pump pumps out? WELL, when the system is started the sumps are filled along with the pond and the pump tank. The system starts and the water flows around the system. The pump tank loses a small amount of water via an overflow until the system balances out. It does this because on average it can only receive what it pumps out and so the time arrives when the pump tank is at max but the sumps are empty. This means nothing is returned to the pond until the next grow bed empties. Due to the size of the pond it doesn't stop instantly overflowing when the sump is empty it just gradually reduces its overflow. The pump is still pumping and before the pump tank is empty the grow beds have flushed and re topped up the pond........ The pond never changes in height more than 1cm.

This system has been running constantly now over the past few months and the only top up needed is when I drain the solids from the swirl filter. I remove 10L and replace 10L.

It sounds complicated because it was, but once regulated it gets boringly unnecesare to fiddle with as it just regulates itself.

It's less complicated than this post........ KE

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White spots on plant leaves and very very hard water could just mean it's winter!

With the first 2 grow beds built it was time to build a table for the filters and header tank.



It had to be level and the outlets on the header tank had to be above the height of the grow beds. You can also see the black plastic I used in the IBCS to cover up the (slightly) uneven sawing.

Here it is with the filters etc in position.

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White spots on plant leaves and very very hard water could just mean it's winter!

You may also notice that I have slotted two of the header tank flow valves into a restraint. This is to stop any chance of the header tank being damaged if anyone decides to fiddle with the taps.

Another thing to notice is that after breaking my original header tank I replaced it with a UV stabilised same dimension tank.

Next up was connecting the first grow bed I made and hoping my calculations were correct about flow rate.

It needed a little bell siphon and flow feeder tap tweaking And then it began working. It now works like clockwork hooray!

One bed fills and fires every 29ish minutes and the other every 25ish. They both empty in 5.25mins

Once I knew my system worked it was time to remove the temporary pipes and dig a hole for the pond ......

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White spots on plant leaves and very very hard water could just mean it's winter!

I opted for a plastic pond as opposed to a liner simply because we get moles in our garden. They manage to dig everywhere you don't want and I didn't want one disturbing the pond edges and causing a leak. It was so much simpler to just dig a hole and drop a plastic pond in.

That said there was not a great deal of tolerance between the pump tank and the inlet pipe height, 5 cm to be exact. Which meant getting the pond not only level but as close as possible to the middle height of the two so water could flow in and overflow out.

Hole started





Pond ready to go in

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White spots on plant leaves and very very hard water could just mean it's winter!