Backyard Aquaponics
A place to discuss aquaponics

Hello one and all,

Been lurking and reading for a few weeks and thought it about time I said 'Hi'. I don't have a system yet, nor even any materials, just lots and lots of ideas.

I live in London and it gets pretty cold here, especially at this time of year. As such, I'll be growing most of my plants under the cover of an 8ft x 10ft (1920mm x 3158mm) greenhouse which we ordered yesterday and has yet to be assembled. In fact, negotiations have resulting in aquaponics only being given half this space. The rest will be used for dirt gardening.

So, my intention is to put a set of 1200w x 600d x 900h shelves on one side of the greenhouse. There'll be a 300mm high GB on top, 400mm FT on the bottom. There's no room for a sump so it will be a timed flood and drain with the FT volume dropping (by a third?) as the beds flood.


By my calculations: Each growbed will be around 200L (44gal), and each fishtank will be about 250L (55G), trying to keep a 1:1 ratio with a little extra in the FT to accomodate the fluctuating water levels.

My question: Can I raise carp (or trout) to table size in a 200L (55g) FT? and if so, how many fish should I stock it with?

My initial thoughts are based off 3KG fish per 100L of GB, so 12 x 50g fish in my 200L system?

I'll put two of these shelving units next to each other and will connect the tanks together to share the water so I only need one pump, but the fish won't be able to swim between.

Hope this makes sense. I'll try and add a sketchup shot later!

Many thanks for your input,

B.I.F.

Hi BIF
you will probably get away with carp at that stoking ratio, Trout from personal experience I would use half the number.
If you are going to do flod&drain you will only turn half the water in the FT every one hr , the goal is to turn(cycle) that amount of water at least once per hr, and if you give two cycle in one hr you might end up with some plant not liking to have wet feet, and eventually dump off and die.
Another factor is putting Ft in a polytunnel the temp will influence your water and witha given depth of 40 cm in you FT it will take a few hr for the trout to cook up.
the best you can do is to dig the FT in the soil and it might help but noo guarantee.
I've started my first system in London 2 year ago, as well as I was giving advice to FARM:shop and I did maintenance job on the aquaponic system the have, have you been there?

Hi BioAquaFarm,

Thank you for all the info, I was looking at the pictures from your London set up this morning, very impressive! One day I hope to get permission to spread out to that extent.

I went to Farm::Shop recently, but sadly only when it was closed - I still had a good peer through the window at their set up, the tilapia looked very happy in their tank. I'll definatley have to pop in when it's open and have a good nose around

The plan for turning over the water is to get a decent size pump, so even if it's only running for 15 minutes an hour it'll still turn over the water in the FT at least once (if not twice) in that time. Perhaps the Laguna Max-Flo 6000 or 7500. So the GB should fill up in the first 5 or 10 minutes then overflow for the rest of the 15 minutes. Hoping all that water moving around will help with D0 too. I don't think I'll bother with a siphon as they don't seem to make that much difference.

I'm thinking to start with Carp, I hear they are much more forgiving and I need all the forgivness I can get while I'm starting out. Trout can wait for another day when I have a bit more experience. I've read that the ideal temperature for carp is 23-30 so I hope they'll have a great time in the greenhouse here. It'll be vented so shouldn't get much above that (I hope).

How are things going in Somerset? Get you get any head-way with the bureaucrats?

Yes, all the burocracy has been sorted, Aquaculture Production business licence has been obtained, in june we still have to get the Food Standard Agency to come for the processing facility inspection, farmers market are in stand by waiting for our production to be ready, yesterday the first 300 trout have been stocked from now on every month and a half we are getting the same amount, still waiting on my carps and perches, they should be here in the next few days.
Somerset food/growers comunity it's revealing very helpfull, I'm also running a program with Incredible Edible Somerset as a master gardener to help 5 family to grow food, it's a one year volunteer project.
Next month building of the second Polytunnel (DWC and Ebb'nFlow) and a third section for 1000 NFT holes will begin, and until june we will be mainly working on the farm, we have wormery, ducks, bees, and soon we'll get goat and pigs.
It's a busy farm life.


CIAO

All I can say is Wow! Is there a system thread with some pictures I can take a look at? Sounds amazing, I'll so have to visit the next time I'm in somerset. I wish you all the best with your endevours!

The thread is (newsmall venture started in UK), soon our website will be launched and then you can follow our progress.
If you would like to pay a visit you are welcome, just let us know beforhand.

Take care

The promised first sketch of my planned system, still not certain it's big enough to raise carp to table size...

Any suggestions?

The over-all height of the greenhouse is accurate, but the eves are actually a bit lower than that I'm afraid.

Plan is timed Flood and Drain as I don't want to run the pump 24/7. No room for a sump tank so CHIFT PIST is out I'm afraid.

I don't really want to dig a hole to submerge the FTs as the plan is to make this removable should it all go wrong!

I was wondering about how best to connect the pump from the Pump to the GB. Do most people use PVC pipe? What size for a 7500lph laguna with an 8mm outlet? Should I just put a T piece in to split the flow between the beds?

I guess the sensible option is to take the pump plumbing up the outside and over the edge of the growbed. Since I'm so tight on space I'm thinking of going up through the base of the beds (1/2" ply with epdm liner) using uniseals. Anyone tried this? Can anyone else foresee problems?

I'll try and add the plumbing to the sketch at some point but it might take me a day or two...

That's a massive pump for the size of your system. Whatever you do try and include a t piece to direct excess water volume straight back to the FT.

Will

Thanks Will, I was working on the principle of turning over the volume of the tank each hour, while running the pump for only 15 minutes an hour, at a head of 5' (about 2-3' actual head, and some extra for frictional losses in the pipe).

I looked at the 3500lph laguna, but it only had 1000lph flow at 5' head, which would only turn over half the water in 15 minutes. The next step up (6000) could turn over twice the tank, but the 7500 is only £15 more and can turn it over three times and has an 8mm outlet instead of 6mm.

Is there such a thing as too much flow? I've head it aids aeration.

Also, do these laguna pumps mind being switched on and off like that?

I will definatley redirect some back to the tanks, thanks for the suggestion

Get the biggest bang for ya buck... just divert excess flow as suggested for extra aeration...

Haaving a larger than required flow rate.. just gives you room for expansion later...

You could have too much flow...

Into your grow bed... if you clay balls and plants are flying out of the bed... or your siphon wont start...

Into your fish tank.. if you're fish are grasping the side of the tank... panting from excersion.. or exhaustion...

Thanks Rupert! I should point out here that the rest of the greenhouse has been designated for my better half to grow things the 'old fashined' way, so room for expansion is limited.

Not to say I can't get creative later - 'his and hers' greenhouses maybe!



If anyone else has any idea how many carp I can fit in those 200 odd litre fish tanks, and if they'd be happy getting to plate size (500g?) in them, it would be great to hear. 12 in each is my current plan...

How many fish you can have.. and grow to plate size (500gm).... is totally unrelated to the fish tank size.. generally...

It's a matter of how much filtration you have.. to cater for the feed rate and wastes.. at the maximum size...

Having said that... a 200L fish tank.. is a small tank... visualize how many plate sized fish you can have in that volume... such that the fish can actually swim/turn around...

Or visualise how a 500gm plate sized fish would look... in a 20L bucket... and then according to your ethics or comfort... figure out how many you fish you could fit...

Should I take from that that you think 20L per 500g fish is not enough? (I'm assuming I'll have a few loses before they get to that size btw). Is 30L a better number? 50L?

Perhaps I should start a new thread with a poll... how much space do you think a fish needs to be happy? Does it depend on the type of fish?

That's the information I'm after, I really don't know and I'd hate to do something cruel through lack of experience.

A bigger pump give you room for expansion and....a high energy bill, plus fish get stressed every time that turn on, just like you live under aheathrow runway! I personally used Fishmate 4000L, has a low wattage and high head pump (they are not cheap but save on the long run, and still leave you enough pressure to have hanging basket or some strawberry tower too, you are looking at moving 100lt in 15 min and that can be done even on a pump that carry at least 2000ltx hr (account for pressure loss).
Areation is the key, good quality japanese ceramic aristone and a small air pump are way efficient(20ltx min at least,this only use 15 wattxhr)
do not rely on areation from a diverted water pump, if the pump stop working you end up with carp soup!
Filtration wise I was personally running 2 cycle in one hr to have a decent filtration (15 on 15off 24/7)
(100lt cycled every 15 min=200 lt x hr been cycled)
8mm pipe is too small to get the job done, I would use not less than 21mm EPDM hose or 21mm PVC waste pipe(cheaper alternative)
Insulation is the key if you can not burry the FT, anything needs to be insulated and shaded, in summer you can get some shade netting(debris netting) to keep temp down in your GH.
Uniseal? US only and you get them on ebay.
I personally do not trust any push-in fittings, over time they tend to come loose, leaking, craking etcc.
Look for (Bulk head connectors) or (tank connector) from plastic pipe supplier, normally they are srew on and have double rubber seals.
If you achieve a proper filtration then you can have 4/5 carp in your tank.
And that is pushing the limit, I would start with 3 and you can always add more, they are not cannibalising like trout if you introduce more fingerling at any time.
Trout is not so good at FCR (food conversion ratio) compared to trout (triphloyd only).
Do you want to eat the fish?
The problem in London is to get fish fingerling, if you go to farm:shop maybe you can get a few from them (tilapia)
I would add some filter foam on the GB inlet to help removing part of the suspenden solids.

have fun!