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Our aquaponics journey: failures and successes and the born of the most advanced aquaponics smart device

Two months ago we posted about our test-aquaponics setup, that is controlled by the Aquashield and since then we received a bunch of questions about the device and was asked to shoot some more photos about the functions and parts, so we did that, here we go 🙂

We also thought through the whole aquaponics experience and decided to write down all the failures and mistakes, so maybe others could learn from it and save the frustration (and some fish also).

Here’s a more detailed description about our test aquaponics site’s history.

Monitoring the new setup

We started the first version of this IBC setup in 2015 (way before starting the development of AquaShield). It was a simple setup with 2 growing beds, a sump tank and a fish tank, with the total volume of 1200 l ( 320 gallons).

I know, it’s rough around the edges, but hey, it was our first project

That was the first time, when I thought maybe we should use a solenoid valve to control the flood-drain cycle (learn more about it down below).

I hate to build bell siphons so much….

We knew very little about aquaponics back then, so we did some more mistakes, but the system was working and we started growing lettuce and basil. We completely missed to cycle the system, so the plants have a rough start but after 2 months, the plants started to turn yellow and die off slowly. We didn’t know, that there was not enough nutrients (there just wasn’t enough fish in the tank for so much plants) in the water as well as the growing light didn’t provide enough light for the plants.

In hindsight the water was also too hard (we used tap water), so the PH was well over 8, no wonder that the plants didn’t like it. The final blow for the system was, when we introduced some new fish to it and they just brought some new pathogens and killed all other fish in a couple of weeks.

Poor – already ill – fish introduced to my system

So the project ended up pretty badly and we didn’t want to build a new one because we just felt, that too many things could go wrong and we don’t even know what was the exact problem.

Then it hit me: I’m an engineer, so I just have to over-engineer this! Back then I was quite into smart homes and started to sketch a smart home system for indoor farms or greenhouses, specially for aquaponics.

I knew, that I want to monitor different parameters and I also want to control the setup based on these values, so I came up with a system that is an integrated monitoring and controlling setup and is connected to the internet, so it can alert me and provide me access to the system, no matter where am I.

New aquaponics test site controlled by the first AquaShield (1.0)

This aquaponics site was controlled by the AquaShield 1.0 in the last 1,5 year and it was working fine, but now, with the AquaShield 2.0, we will just bring the whole system to a new level.

The new test-site controlled and monitored by the AquaShield 2.0

Let’s see all the features and advantages that AquaShield could provide:

Start with the most basic thing, the flood and drain cycle. For a well-working aquaponic setup you should be able to pump the whole mass of water in every hour through the system. Also it is optimal to water your plants for 15 minutes (in every hour) and drain the water for 45 minutes.

The reason is that the grow bed now has taken on the additional role of being the filter for the fish waste. If you only ran the fish water through the filter every four to six hours, fish waste would build to dangerous levels. We also installed an other biofilter just in case. This biofilter also acts as a small waterfall at the top of the fish tank for aeration.

Has a nice acoustic as well

In our case, that means we would need a pump, that could handle 1200l in 15 minutes (that means we need a pump, that could pump 4800 l every hour).

These types of pumps don’t really like to be switched on and off regularly. We know this, because we broke 3 of them before changing the system’s flood and drain cycle to be controlled by a 200V solenoid valve.

Solenoid valve built in to the drainpipe under the grow bed

So we ended up with a 5000 l/h water pump, that runs continuously and have a solenoid valve, that controls the flood-drain cycle. We also added an overflow (that is the second white-pipe tower with the green cover) that keeps the water level just 5cm below the grow media’s surface, creating a dry-zone for the plants.

The left one is controlled by the solenoid valve and the right tower with the green cover is responsible to handle the overflow

One more important thing: we used fixed PVC pipes for the pump, so it won’t curl up or move anymore (I suggest you to do the same, it will save you from a headache).

The water pump is always switched on by the AquaShield, but I can easily switch it off for maintenance or to feed the fish (so I can watch them at a clear water surface :D).

Water pump control tile on the AquaShield Connect’s main dashboard

Just after starting our first aquaponics setup, one of the fittings broke and the pump almost depleted the fish tank, as it pumped the water to the ground instead into the grow bed. To prevent this, we installed 2 water level switches to the fish tank, that is monitored by the AquaShield.

When the drain pipe is getting clogged and the water level reaches the maximum, the level switch will alert you

These 2 sensors alert the AquaShield, if the water level reached the minimum and also send an alert, if the water level exceeds the highest point (that is at the top of the overflow pipe). With this, leakages and overfilling are not an issue anymore.

Future plan is to add a valve (controlled by the AquaShield), that could open the RO water inlet for topping off the fish tank.

Minimum and maximum levels are monitored by 2 simple level switches (this one is for checking the maximum level)

The grow light is a 600 W HID lamp, that works just fine for the single grow bed. When we started the first setup, we didn’t know, what amount of light should be delivered to the plants to keep them happy. Once we learned this, we started to use some handheld brightness meters. With the AquaShield 2.0 you will get real-time LUX readings and would be able to check all previous data. With this, you will be able to determine, if your plants got the optimal amount of light or not.

The new Humidity and Light module (also measures temperature)

With the new Light and Humidity module, we know for sure, that there is enough light for the plants.

With AquaShield 2.0 we could also measure the relative humidity (and the humidity sensor also hosts a temperature probe), so based on these we will be able easily optimize the environment using an evaporator or a dehumidifier.

It is also capable of measuring VPD (vapor pressure deficit). VPD controls plant transpiration rates, stomata opening, CO2 uptake, nutrient uptake, and plant stress. Once you mastered the VPD you will be able to optimize nutrient uptake and grow better.

With aquaponics, the biggest issue (for us) was always the fish. For calculating the fish density, we used a simple rule of thumb (based on Sylvia Bernstein’s book): for the optimal plant growth, you should keep 1 kg of fish for every 60 l (16 gallons). That means, we should keep 20 kg of koi for the 1200 l system.

Our plan is change this and use rather the feeding rate ratio (FRR) method. This relates the amount of feed to plant growing area per a unit of time. The optimal FRR is somewhere around 25 g/m2/day. Of course we don’t want to measure the fish food by hand, so we will connect an automatic fish feeder, that will feed the same exact amount every time. We will also monitoring ammonia and trying to understand the FFR / ammonia dependency.

At such high fish density there are a couple of things, that could go sideways (fast).

First and foremost: dissolved oxygen. All fish need at least 5 mg/l dissolved oxygen to survive and even more to thrive. If the flow of water stops or the tank doesn’t have good aeration, the whole stock could suffocate in a couple of hours. The avoid this, AquaShield has a dedicated DO (dissolved oxygen) input, that reads a DO sensor real time, so we can monitor this parameter or even set up alerts. Our system alerts me – send me an email with the subject of “ALERT – too low dissolved oxygen” – once, the DO drops below 5 mg/l for more than 5 minutes.

Although fish tolerate PH swings better than low amounts of oxygen, it is still the second most important parameter to watch, not to mention, that PH plays a major role in the development of plants. Similar to the DO, PH is also monitored continuously.

We also set up a warning for PH, but in this case we defined a range for the alert: the AquaShield monitors if the PH is higher than 5.5 and lower than 7.5. Otherwise we receive an alert with the subject of “ALERT – too low/high PH”.

It is important to know, that PH is compensated by the temperature, that AquaShield monitors also.

Next to PH and DO, we also track ORP and EC.

ORP is responsible to provide feedback about dissolved oxygen from another aspect. Nitrifying bacteria need an adequate level of dissolved oxygen in the water at all times in order to maintain high levels of productivity. Nitrification is an oxidative reaction, where oxygen is used as a reagent; without oxygen, the reaction stops. So in short, you have to keep dissolved oxygen at an optimal level to grow healthy plants and ORP helps you to achieve that!

In an aquaponics system, keeping the ORP of your water and nutrient solution low is recommended. Organic growers intentionally add beneficial bacteria, such as mycorrhizae, to their nutrient solutions to help stimulate plant growth.

Electrical Conductivity, is a measurement of the salts in the nutrient reservoir, which tells the hydroponic gardener how concentrated the nutrient solution is. This works because hydroponic nutrients are generally delivered in mineral salt form. Aquaponic plants, on the other hand, are fed by the organic waste from the fish, which has very little salts. EC is therefore not as a useful measurement for the concentration of nutrients in an aquaponics system as in a hydroponics system.

These parameters help us to optimize the aquaponic setup as well as identify if there’s a problem with the system.

For the AquaShield 2.0 we also added a new 0-5 V input and with this, we will be able to add nitrite, nitrate and ammonia measurement to the monitoring arsenal. (We know that is super-overkill, but you know, we just love over-engineering stuff.)

Our new “0-5V” JOKER card

I know, I know, it’s TLDR 😀 Anyway, I was happy to share this with you, as the love of aquaponics was the catalyst to build the AquaShield for exactly this community.

PS: We are launching our Indiegogo campaign soon, check out page for more information here: https://www.aquashieldcontrol.com/smart-aquaponics-with-aquashield/

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