Backyard Aquaponics
A place to discuss aquaponics

After long searching, I fixed 20 tilapia fry a month ago. They have been growing very well, so before they outgrow my 65L tank I have started constructing my second setup.
My first setup:


Ive started constructing the 2.0 setup, it consists of a 250 liter fish tank, a 100 liter solids filter filled with clay aggregrate and a square meter of pvc pipes in which ill put small net pots with clay. Above all that will come a LED of 150 watt to provide the light.

This is my 2.0 set up so far:


I still got some small things to do:
- Last missing piece of pvc to connect the solids filter
- fix LED above my growbed
- fix some curtains around the led so I dont go blind/have the police on my doorstep expecting a marijuana farm
- buy small net pots, which are a real hassle to find in europe.


Hopefully I will be able to finish it tomorrow and start stress testing all my connections so I dont flood the garages underneath my appartment. And then start cycling my system. Im planning on adding a little bit of water from my small system everyday, so the system (hopefully) has a flying start.

Im really loving building and constructing this set up! Lets hope my plants and fish love it just as much..

Comments are more than welcome!

Almost done with my new setup, fixed all the plumbing and put my LED in there.



should be sufficient light

My set up is done and has been cycling for 2 weeks without fish and 1 week with 2 tilapia fingerlings in the tank. Here is how it looks now:


Plants grew well, but the new leaves are pale green and show interveinal chlorosis. I thought it could arise from either a low light intensity or a iron deficit. Measured the light intensity which is high enough, so probably a lack of iron.

I have some iron chelate laying around and I am wondering if I should add it, or wait for my system to mature and the pH to drop so more iron becomes available for plants. I dont like putting chemicals into my system so I will wait it out for a bit

Furthermore I bought a seneye reef ammonia/pH/light measuring device, which is really awesome for datalogging all the waterparameters. My water values over the past week:


From this data I would conclude that the NH3 converting bacteria still need to increase a bit. The NO2 to NO3 converting bacteria are established well enough to add some more fish and the NO3 is taken up enough by the plants as well.

So my plan is to wait till the pH and NH3 will drop some more till 7,5 and 0,01 before I add some more fish. The pH is going down slowly the last few days, which indicates my system is maturing and also lowers the amount of free ammonia.


Any comments?

Sounds like a good plan! You'll probably get another ammonia/nitrite spike after adding more fish, so keep an eye on that.

You could give your plants a foliar spray to give them an iron boost before your pH drops, too.

All going well with my system, tilapia have grown quite a lot. Ive estimated that they have grown from 1,5 cm to 9 cm in 90 days. So I think they are doing quite well.


I started feeding them black soldier fly larvae, which they seem to enjoy as it results in a feeding frenzy. Going to slowly increase the percentage of BSFL of the total feed, till about 50%. My guess is fish know what they want to eat and what is healthy for them. How else would they survive in nature? So if I see the fishes their enthusiasm for the BSFL decline, I know it does not provide a balanced diet for them anymore. I've produced almost 500 grams of BSFL in 4 weeks, so I can feed lots and lots of fish with them haha

Plants are not doing particulary well, but with a pH of 8,1 I figured they are seriously nutrient starved. Not going to add any chemicals, pH is going down pretty steady and will fix it eventually, else Ill sow new seeds. I did have a serious pH fluctutation, it went up from 7,8 to 8,1 overnight, but going down again. The only thing I changed was a little bit more waterflow through my pump. I do not see how that can have any influence on the pH. It probably increased the oxygen content of the water, but that would make the bacteria work harder and thus excrete more H+, so no pH increase. Maybe more CO2 is lost from the water, as it is more disturbed by the waterflow?

Ow yeah, about adding chemical nutrients, is it possible to maintain a system without adding any iron? Im reluctant to start adding nutrients, as Im very scared of killing my fish. But all the EDPTA-iron chemicals should be safe?

My free ammonia (unionized ammonia) levels are fluctuating through the day between 0,015 and 0,04. I read alot of people on here who argue that NH3+ should be 0, but how precise do they measure there ammonia lvls? Ive read in literature, they used 0,004 as a control treatment and furthermore 0,01 0,05 0,1 0,15. The 0,01 and 0,05 treatment showed no significant difference in growth compared to the control treat. The 0,05 treatment did show about 25% less hemoglobin in the blood, which is not ideal I guess.

The ammonia toxicity is affected by temperature and pH so those are what dictate the levels you can run before you start killing fish. Most people are using the API test kit which measures total ammonia and isn't very accurate but gets the job done most of the time. The bacteria processing ammonia usually reduce the ammonia to near or at zero so having a reading with the API test kit especially during warm periods or with high pH is telling you to back off on the feed. It's not uncommon to have a trace reading though and how it's gets interpreted depends on the environmental conditions. Those conditions determine whether ammonia is in the more toxic form or not. Here's the table used for figuring ammonia toxicity - http://ibcofaquaponics.com/information/tables-and-charts/

Not my best explanation of this . Even knowing the toxicity, fish species are not all equal

I think the temperature and pH dont affect the ammonia toxicity, but they do affect the amount of TAN which is in the toxic free nh3 form. So if you measure the nh3 and not the TAN, the toxicity should be at a certain level of nh3 irrespective of pH and temperature. Not my best explanation either haha

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Hmm

Yes, well, I think you have it. As you mentioned the unionized (NH3) form is the toxic form. Yes you are correct that if the unionized form exceeds a certain amount it is toxic regardless of the temp and pH but the temp and pH determine the balance between the two forms (NH3 and NH4) and if you're measuring the TAN (which is both forms combined) the table tells you how much TAN results in a toxic level of the unionized. I'm not sure what they used for the toxic level determination when they made the chart I linked to . When talking about the study you mentioned, it showed lower hemoglobin at 0.05 so you get some effects at very low levels. Another species of fish might have died with this level in conditions that weren't ideal (like trout pushing their temperature limits for oxygen availability as an example).

Allright, my aim for nh3 is than set at <0.01.

Does anyone have a bright idea for sowing seeds in small net pots with claybeads? Or do I need to transplant them later?

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What are you trying to sow? I'm just starting out too but I germinated some lettuce no problem. I was actually a little shocked. I just threw in a handful of seeds and ruffled up the surface a little. It was easier than soil!

You can do it either way. You could probably start the seed in your system if the temps are warm enough. If you have a way to raise the water level in the pipes for starting seeds that helps, otherwise, dampen the media in the cup and drop the seed in - it should stick to the moist media. You'll have to keep it damp by using a spray bottle if the water level in the pipes isn't high enough to keep the lower part of the pot moist. It's sort of a balancing act since this also can promote damping off.

You can also start them outside the system with a tray of water to keep the media in the pot moist to the right depth. Warm the tray for starting warm weather plants like tomatoes, peppers and squash.

Thanks for the tip, sown them right away. The previous time Ive sown my seeds in some vermiculite and when they were big enough transplanted them to the clay media. The results were very poor, all my lettuce fell over. The rootsystem is not growing in the clay to anchor itself but only growing in the waterstream underneath it. But I think sowing them in the right medium right away might prevent this.

Made a picture of my plants. Its a mess in there but atleast everything is growing. Ive sown seed to replace all the pots in the pipes with lettuce, parsley and basil. I need to have a uniform plant height else the light intensity they get from the LED is different, as you can see from the tomatoplant in the back. Im building an extra LED to hang above the potatoes on the left side, so I can lower the LED for the other part.


Ow yeah, I also ate the first homegrown produce, lettuce! It was very soft and tasty.

On the lettuce falling over - The roots don't really attach to the clay very well and that's normal. My guess is it's mostly about the light. Another possibility, sometimes the new clay will float but give the illusion that it's resting on the bottom. You plant and overnight the plants will shift position, disappear, or fall over.

Probably the light you're getting will do the trick.

Just ran into your topic by chance. I'm also starting an indoor tilapia-LED-aquaponics system, in Wageningen. What a coincidence! (Wageningen, the Netherlands is a town of less than 40.000 people..)
My fry (I only have 9) have grown from 1 cm to 4-7 cm in the past two months. We should meet up some time!