aquaponics effect on sealed room co2 levels?

[HyDroid]

Short answer:
average of 535 mg O2 consumed per hour per kg of fish

Long answer:
Do'h! Good call ornamental Sorry for the bad advice, bajan.

I'm trying to think of a way to do this without a CO2 meter, which is probably pricey. With the CO2 meter you can just put the probe in the headspace of the sealed bucket and it should work from there (minus what gets left in the water, but you really want to know what comes out of the water).

I thought about tracking the rate of ph change of the water but it seems like the amount of O2 in the sealed environment might not be enough to change the ph significantly before it was used up.

Since I failed to devise a proper experiment I just looked it up:

http://link.springer.com/article/10.1007/BF00347007#page-1
(second page of preview has a table)

http://www.scribd.com/doc/16363005/Oxygen-Consumption-of-Tilapia
(use full view)

There is some other interesting stuff in the second link, don't be fooled by random 'download' ads.

 

[HyDroid]

I think that I can take two things from your comments, Ornamental:

1.) It looks like fish require more nitrogen and other things to stay running than the plants they can support with their CO2 can provide in waste (dead plant matter) so the closed loop isn't going to work very well. In other words, something with a higher metabolism / biomass ratio is going to be necessary.

2.) It will be hard to keep microbes out.

So why not cut out the middle man and just use aerobic bacteria to breathe the O2 back to CO2?

It might be easier to achieve equilibrium if you can easily control the temperature of the microbes. Use a PID controller based on CO2 levels to control the temperature which controls the metabolic rate.

Then it's easy to stockpile a hoard of dead plant matter in the fermenting solution big enough to buffer the fluctuations.

I think I'm off topic by now.

 

[Only Ornamental]

You don't need aerobic bacteria, just plain and simple yeast like those used to make bread or beer . It doesn't matter what the microbes use as long as they 'breath off' carbon dioxide, right?
That's the way poor men supplement CO2 for their aquaria.
Well, I tried it as a teen and it didn't went well; forgot the 'brewing jar' and it overflew... what a stinky sticky mess!

But with a cheap bubble counter and this siphon shaped tube (forgot its English name) you should be able to built something suitable yourself. Temperature control works fine; you just need to take aliquots every few days (or even every single one) and judge the amount of yeast by turbidity! That's how it's often done and is really reliable. Simply take the same shade of grey-milky hue every single time or buy some lyophilised bakers yeast and always add the same quantity of beads to the new nutrient solution.

Way less money, less troubles, less nifty stuff, less time, less fodder but still more gain! Well, the smell gets really bad if you don't change the brew every few days...

And I'm completely OT too, LOL!

 

[HyDroid]

But what happens to the free O2 levels if there are no (strictly) aerobic organisms? Shouldn't a growing plant net O2?

 

[bajangreen]

So much I have to learn..... don't have access to a co2 meter so that option is closed.

In an Aquaponics system they are plenty bacteria, they convert the fish waste to plant food, may be they also convert the carbon as well?

 

[Only Ornamental]

But what happens to the free O2 levels if there are no (strictly) aerobic organisms? Shouldn't a growing plant net O2?

Sure, but you open the tent now and then and there will be no 'oxygen overpressure'. At 20% oxygen, a bit more or less doesn't matter (unlike CO2).

So much I have to learn..... don't have access to a co2 meter so that option is closed.

In an Aquaponics system they are plenty bacteria, they convert the fish waste to plant food, may be they also convert the carbon as well?

Well, you would see if you had too much CO2 (plants stop growing and the fish pant for air) but with fish you're likely below the plants limit (unlike with yeast).
And you're right concerning microbes, they break down the remaining carbon sources and give off CO2 as well.

 

[2 Legal Co]

The fly in the ointment (I think), is the need of the fish for Oxygen.

I do not have the scientific background to do the math.... however, having operated a Tropical Fish Store in another life....... if you overload the water, and do not take steps to re oxygenate it before returning it to the fish tank...... you will have dead fish to add to your problems.

I've looked into what people on Youtube are doing with aquaponics. It appears that aquaponics work very well in the propagation and cultivation of 'flora'. Cannabis being a fast growing plant (for the most part), it should grow well in the standard aquaponics environment.

Most of the systems that I've seen on youtube, have come to require additional filtering for 'solids' removal, prior to going to the planting beds. Ostensibly this is to keep the 'mud' from building in the beds.

Admittedly, the only experience I've had with cannabis and 'fish water', is that last year I watered a couple of plants with water from a fairly 'high' mountain creek. In spite of receiving advice Not to use stream water (as it supposedly was too high in mineral content)..... The plants benefited visibly from the switch from well water to stream water.

The advice tendered about using a larger capacity system is most valid. The smaller the system, the more volatile the changes in the water chemistry.

I'll be following this thread to see what your results are, as I'm considering a small greenhouse. It's currently on hold until I decide where I want to spend my time annually. lol I'm interested in growing fruits and vegetables, in addition to Cannabis.

Due to the limited numbers here in Co., I may not take this idea to fruition at all.

 

[2 Legal Co]

I think that I can take two things from your comments, Ornamental:

1.) It looks like fish require more nitrogen and other things to stay running than the plants they can support with their CO2 can provide in waste (dead plant matter) so the closed loop isn't going to work very well. In other words, something with a higher metabolism / biomass ratio is going to be necessary.

On the 'Aqua' end of the project...... Nitrates/nitrogen, are toxic to the fish in the system. Much is done to lower/speed conversion to gas, so that it can leave the water, allowing the fish to live.

Just a thought.

edit; FYI... if/when you set up the system. You MUST start with limited plants and a very few, expendable fish, as the system will 'bloom' with bacteria (water will cloud). This needs to happen Before you stock the system with the 'normal' fish inventory.

Reason being the 'bloom' uses up the oxygen in the water and the fish will suffocate. Normally, this will cycle within a couple of days and you can start to add inventory on both ends. Adding 'air stones'. or 'waterfalls' will add to the oxy levels and keep the fish swimming.

 

[Only Ornamental]

The fly in the ointment
.....
if you overload the water, and do not take steps to re oxygenate it before returning it to the fish tank...... you will have dead fish to add to your problems.
......
Cannabis being a fast growing plant (for the most part), it should grow well in the standard aquaponics environment.
......

Never heard of a fly in the ointment . What does it mean and where's the link between insects and body lotion?

Good that you mention the oxygenation of the water again. Really shouldn't be forgotten; and additionally it helps to 'degas' the water of carbon dioxide.
Also the needed filtering step; might be good to spend some time considering the different options (like passive sedimentations/skimmer v.s. filter pump). I'd go for a bubble air pump in the fish bucket for oxygen, a second bucket without current for sedimentation and skimming followed by an external pump (eventually an internal one in the second bucket) which uses ceramic granulate and turf as filter material (2 legal co can surely help with that!). Turf is a great thing for fish and cannabis; gets the pH down to 5.5, adds humic acids, and removes quite a bit of harmful stuff and heavy metals. Although, you may lose some of the trace elements but at the same time don't risk toxic accumulation of these in the fish tank. Use the old turf afterwards in your garden/compost.

Cannabis does very well in hydroponics and grows well with aquarium water so it should thrive in aquaponics.

 

[2 Legal Co]

Never heard of a fly in the ointment . What does it mean and where's the link between insects and body lotion?

Good that you mention the oxygenation of the water again. Really shouldn't be forgotten; and additionally it helps to 'degas' the water of carbon dioxide.
Also the needed filtering step; might be good to spend some time considering the different options (like passive sedimentations/skimmer v.s. filter pump). I'd go for a bubble air pump in the fish bucket for oxygen, a second bucket without current for sedimentation and skimming followed by an external pump (eventually an internal one in the second bucket) which uses ceramic granulate and turf as filter material (2 legal co can surely help with that!). Turf is a great thing for fish and cannabis; gets the pH down to 5.5, adds humic acids, and removes quite a bit of harmful stuff and heavy metals. Although, you may lose some of the trace elements but at the same time don't risk toxic accumulation of these in the fish tank. Use the old turf afterwards in your garden/compost.

Cannabis does very well in hydroponics and grows well with aquarium water so it should thrive in aquaponics.

lol I forget that a lot of you aren't my neighbors, or even in the USA. Ya got me.

I've forgotten most of what I knew of aquarium keeping. It only seems to show up intermittently now. I sold the fish store in 1979, so I guess I should expect that? Being in Colorado, it's been somewhat of a different world, as MJ is at least quasi legal here.

 

[audiohi]

I know of one large scale aquaponics operation that does collect co2 from their degassing, but they spent BIG bucks to do it, and won't share their success in that department. That leads me to believe it was a big waste of money. I'm sorry I didn't read through the thread fully, but I figured I'd share that bit of info.

They were running 6 20,000 gallon tanks very densely packed with talapia

 

[2 Legal Co]

I know of one large scale aquaponics operation that does collect co2 from their degassing, but they spent BIG bucks to do it, and won't share their success in that department. That leads me to believe it was a big waste of money. I'm sorry I didn't read through the thread fully, but I figured I'd share that bit of info.

They were running 6 20,000 gallon tanks very densely packed with talapia

120,000 gallons of fish water.

That ought to feed a bunch of weed!

 

[bajangreen]

I want to turn over the water 4 times an hour instead of using a bubbler. In some AP systems they trap the solid fish waste in a seperate container and "process" them by keeping oxygen levels in the water high with air stones, I have read this leads to "off gasing" of no3, co2 etc, however I don't want to collect and/or store the gas. I am hoping that by having the fish in the same air as the plants that they form a symbiotic relationship and exchange co2>o2 at rates optimal,

I know in theory this can work as plants use Co2 and fish make co2.
What i am trying to find out is if the industry standerd of 40g fish feed/m2 of plant growing area produces enough co2 for plant growth.

I keep hearing about ghetto yeast, are they any good links?

 

[Only Ornamental]

Ghetto yeast ROFLMAO...
It is just normal baker's or brewer's yeast (Saccharomyces cerevisiae); see Wikipedia. Here around, every store selling flour (most supermarkets) also sell yeast. Mostly, it is a lyophilised granulate in small sachets, sometimes also fresh blocks of ~40 g. Doesn't cost much, about 20 cents a block, a bit more for the sachets. There are pics of these two forms on the linked Wiki page .

Besides, you do want to 'collect' the gas and stock it in form of weed .
Also for the sake of your fish and your nose, use air stones or whatever to pump the water full with oxygen!

 

[2 Legal Co]

I want to turn over the water 4 times an hour instead of using a bubbler. In some AP systems they trap the solid fish waste in a seperate container and "process" them by keeping oxygen levels in the water high with air stones, I have read this leads to "off gasing" of no3, co2 etc, however I don't want to collect and/or store the gas. I am hoping that by having the fish in the same air as the plants that they form a symbiotic relationship and exchange co2>o2 at rates optimal,

I know in theory this can work as plants use Co2 and fish make co2.
What i am trying to find out is if the industry standerd of 40g fish feed/m2 of plant growing area produces enough co2 for plant growth.

I keep hearing about ghetto yeast, are they any good links?

Turning over the water will help a bit, but moving water that is 'flat' is not the best way to re-oxygenate water. Using 'waterfalls' in the movement is key to high oxy levels..... if you don't want to use airstones.

I see a contraption on youtube that they call 'vortex filters'. These seem to be a popular way to remove solids.....more of a settling tank than a biologic component. But they will provide you with good fertilizer for your other growing needs.

The use of a biological filter is a good idea as well (always has been). We used 'undergravel filters' back when. They seem to be almost extinct now for some reason however. I like the undergravel systems IF you use gravel on the bottom of the fish tank, as it keeps the water moving through the gravel. This keeps the life in the gravel aerobic, which is a good thing.

Biologic filtration is a major plus for the fish health, as it does the conversion from nitrates to N gas. Nitrates are toxic to the fish if the levels get too high. Now the aquarium folks seem to use UV lights, in conjunction with inert filtration, and water changes.

You can just almost 'polish' the water and it will have plenty of nutrient left for the plants. We kept aquatic plants in our tanks, and they did well even though we used rotating power filters weekly to polish the water. Eye candy is important in retail.

Our biggest problem with the aquatic plants was that we had a lot of fish that liked/required higher PH levels. Plants didn't thrive as well in those tanks. Rift lake cichlids don't like anything close to neutral/acid water.

Concern yourself with the selection of fish and their health. The plants will pretty much like life as a whole.

 

[lost in a sea]

you can't get the fish to produce anywhere near enough co2 for plants to notice and the o2 from the plants will hardly be able to increase the o2 levels in the water..

i have to bubble co2 through my fish tank just to have enough co2 for my aquatic plants..

 

[Only Ornamental]

@LiaS: My words . I also supplement with CO2 but have enough oxygen from the fish.
But bajangreen wants to use A LOT more fish than in a normal aquarium plus a high density of land-plants (weed) as well as a sealed environment. That will change quite a bit of what common 'aquarians' experience.
It has as much for it as it has against. He will have to see, learn and adjust...

IMHO a really interesting 'research project'!

@2LC: Undergravel filtration was even before my aquarium time. It has/had something to it and sounded good but I forgot why it didn't pay off...
The vortex thingie became popular thanks to Dyson vacuum cleaners . A really cool technique but better suited for larger volumes.

 

[bajangreen]

Lets start off by clearing this up, Aquaponics work, I have been doing it for a while, I haven't thought about system design, only the numbers,

the reason I want to do this is to not have to buy co2.

I am using 1m2 of plant canopy to 30 gal of water with 4lbs of fish, feeding 40g of 32% protein fish feed. The room is 100 cubic feet. %100 seald. (Well in theory that room will make for better math.)

So as only has pointed out the carbon in the room will come from the fish feed. Witch is 40g/24hr.

Now that I know what the yeast co2 is and i compare to Aquaponics they are some similarities like the co2 is coming from arobic bacteria and it is a relitively small input source.

My understanding of the science and math of the process is to limitedto make a guess at this point I may have to just do it, and see what happens.

 

[bajangreen]

The core question here is how much carbon does feeding fish 40g of feed a day will releast.

 

[Only Ornamental]

Found THIS funny but also interesting blog.
He/she uses a similar approach for the calculation but with the kcal in human nutrition. Bottom line is, a human (~70 kg) exhales 900 gram carbon dioxide per day. 4 lbs fish would produce 23 grams CO2. Using calories instead of gram is a better approximation because it takes 'food process dissipation' (don't know the good word for it) into account (I just took 50% loss). But fish aren't humans; they are smaller and hence need more food due to a higher basal metabolic rate. This brings as pretty close to my originally estimated 40 g of CO2 .

And you're right, you just have to try it!