Aquaponics - My algae farm

My algae farm is working better than I expected.

Unfortunately I expected no algae at all, and got plenty.

But it seems there is a cure.

It turns out algae, like pretty much everything else, needs light and nutrient.

The nutrient I cant do much about, but I can definitely cut off it's light supply. It turns out the fish prefer to feel safer in semi darkness as well, so all I need to do is cover my fish tank.

I chose blue.

All that junk on the ground is the inevitable result of  letting me near PVC with a saw.

I think if I cover the top half of the blue bit where it's visible, and just leave a blue skirt, it might even look ok.

It's a very necessary thing to do as my water now looks like this.

That faint dark smudge on the bottom left is the bottom. It's only 1 metre away and you cant really see it.

That's not so good.

My big concern now is that when all that algae dies, there is going to be a huge spike in ammonia and nitrite as it breaks down, so I've stopped feeding.

On the up side, I have my new grow bed available to take up some of the workload in processing the waste, so I might be ok. I also bought some more media so I can get the second new grow bed online hopefully before the ammonia starts being produced.


My 120 things is 20 years sometimes turns an aquaponics system into an algae farm.

Aquaponics - Nitrogen fixation

I recently had a spike in nitrites that killed two fish. Actually it killed one fish. I killed and ate the other. But they both died as a result of their being too much ammonia and or nitrite in the system.

I put it down to some mistake I must have made with feeding, but it occurs to me that it might be about my peas and beans.

Nitrogen fixing legumes take nitrogen out of the atmosphere, and stick it into the soil. Most plants take nitrogen out of the soil.

I lifted one of my bean plants that's already got beans growing on it to have a loot at the roots, and remembered that in a dirt garden, you rotate crops from season to season, and plant things like beans in a bed before you plant things like tomatoes.

Tomatoes like a lot of nitrogen, and beans put the stuff in the ground. Or at least I think that's what I remember.

But this lead me to wonder if it might be my beans putting too much nutrient into my grow bed that had caused my fish to die.










I'm still at the wondering stage, so don't take this as science or anything, but according to Wikipedia's article on Nitrogen Fixation, the nitrogen goes in as ammonia.

Bad beans.

I also seem to remember that the nitrogen forms on the roots as nodules, in the form of match head sized lumpy things. But I see nothing like that on my roots.










And...

I cant remember if the nitrogen only goes into the soil once the plants die.

But...

I did have a bok choy plant and a bean plant go all rotten on me, so there could well be a connection.

I hope the fish deaths turn out to be natures fault after all.

I'll find out and get back to you if it turns out to be interesting.

Aquaponics - Nitrite Spike

I found some nitrite and ammonia in my system that I don't remember adding.

My nitrite level was at close to 1.0 ppm, and my ammonia was at .25 ppm.

My system always sits at zero for both of those readings.

I added 1 part per thousand of pure sea salt in the form of Sunray (R) pool salt. This was added because it helps to mitigate some of the damage that nitrites can do to your fish. I'm told (thanks TCLynx) that the salt's chloride ion will tend to bond with the nitrite and prevent it bonding with the fishies blood. I'm also told that it's not really a solution, but that it just helps a little.

If you add salt to your system, make sure it doesn't have iodine, or any thing else in it. Everything at my supermarket had an anti-caking agent. (I wonder what happens if you make a cake with salt with anti-caking agent in it)

My nitrite levels are already coming down, and the last time I checked they were at close to 0.25ppm.

By tomorrow morning my readings should be back to zero.

I'm yet to figure out what happened.




120 things in 20 years - not just Aquaponics - Nitrite Spike, but ammonia spikes as well.

Aquaponics - Overfeeding

When I was even more of a kid, my favorite book was about overfeeding fish. It looked like fun.

Uneaten fish food (not poop)

One of the problems with overfeeding isn't that your fish sit in your bath tub and get uncomfortably large and interesting, but rather that the uneaten food sits in the corner going rancid.

A mature system can handle a certain amount of excess food as it breaks down into plant food via the normal nitrogen cycle. My grow bed media is kind of mature, but my water is almost all new from a few days ago when I moved the system.

Most of the nitrifying beasties live in the gravel, but I think there are some living in the water, the slime layer on the sides of the fish tank, and on things like my pump, and pump inlet screen etc. This can mean that, after an upset like a washout and water change, the system might not be quite as capable of turning ammonia into nitrates. I think.

fish so well hidden you cant really see anything

When I changed the water and location of the fish tank there was some inevitable stressing of the fish. Shown here is an image depicting not really being able to quite see the fish because they are still hiding.

As a result of the upheaval, they went off their food.

I think the amount of ammonia introduced into the system by feeding should be similar regardless of the fish eating it or it rotting in the corner, but because I had the option of removing the uneaten food, I removed it.

why do chickens have to stand on whatever you are taking a photo of?

A few days ago I finally tracked down a product I remembered seeing in the shed when I was a kid. It's a siphon for fuel etc, but it has a squishy hand pump so you don't need to drink so much petrol. I thought it would be perfect to vacuum up any uneaten food.

It wasn't.

It didn't work very well at all. That might be why nobody sells them any more.

Aquaponics - Success

Success! I've actually managed to out-smart my fish. This last thwarter was made from a plastic mesh designed to keep leaves out of your gutters.

It's a good thing I'm learning on my small blue barrel system. I'd hate to be making all these adjustments on, and drilling holes in, my big system.

I just spent an hour trying to get my auto siphon to work again.

In order to prevent my fish tank from getting too cold overnight, I tried turning off the pump during the hours of darkness (I now have a small air pump for oxygenation). The downside to this was an increase in ammonia and nitrite levels.

- The nitrates values are divided by 100 so they fit on the graph. (I'm told nitrates can safely be over a thousand, so nitrates are not a concern)

I think my nitrite and ammonia levels are still within safe limits, and it was only for one night, but I've decided to go back to running the pump overnight.

Aquaponics - Water testing

Its extremely important to make sure your water quality is within a desirable range. Aquaponics is remarkably stable and robust, but, for the first few weeks of setting up a new system it can require a little extra care. The best way to avoid any problems is to test your water every day until your system is mature and in balance or "cycled". (pictured here taking 30 days or so)

An aquaponics system is said to be cycled when it can process approximately 1 ppm of ammonia into nitrites and then process those nitrites into nitrates within 24 hours.

A decent freshwater test kit will enable you to get accurate test results for pH, ammonia, nitrites, and nitrates. It will set you back around 50 Australian dollars. They are widely available online or any good aquarium shop should sell them.

If you try aquaponics without water testing you will lose fish unless you are very lucky.

Add ammonia until you see a reading of 2ppm, then wait until your tests show ammonia is 0. Then add more and continue until your system can process 1ppm of ammonia and nitrites in 24 hours. Once you see readings of 0 ammonia and 0 nitrites you are cycled and can add fish.

Plants can be added on the day you first build your system but there wont be much for them to live on for a few days. My house water supply is rainwater and has some nitrates in it from normal environmental nutrient. Even normal tap water will have some nitrates in it so there will actually be something for small seedlings to live on.

Be careful to wash the soil from any store bought seedlings you transplant as they may have any number of additives that may be toxic to an aquaponics system. Growing directly in the grow beds from seeds is safest (and often quicker!)

Conduct water testing every day until you are cycled and then test every week or so or if ever anything strange occurs. Plants yellowing or dying can be a sign of something being wrong with your water chemistry and you might need to intervene in the early stages of your aquaponics system setup. More on correcting water problems later.

Always keep a record of your tests so that you can see emerging trends before they become an issue.

Aquaponics - Fish-less cycling

In order to create a backyard ecosystem we need to establish the nitrogen cycle. The nitrogen cycle turns fish waste into plant food, but perhaps more importantly it turns toxic fish waste into relatively harmless fish waste.

Having no photo that relates to this in any way I'll simply do what all media does these days and use some file footage. So here's a fish I prepared earlier.

The aim in fish-less cycling is to introduce ammonia in some form so that the bacteria that convert ammonia into nitrites can breed up and do their thing. Once nitrites are present, the bacteria that convert nitrites to nitrates multiply. This process can take a while as compared to some other beasties they are slow to reproduce (up to 20 hours to double in population).

Ammonia can be sourced by adding urea (bought in packet form from your hardware store or garden supply store) or by having a healthy, drug/medication free person pee in your fish tank. Within the online forums this second method is referred to as adding humonia or sometimes as peeponics.

In order to set the amount of ammonia correctly you will need a test kit. More on testing your aquaponics system later.