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 - 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 - Pump-less cycling Success!

Sometimes, I know things like cycling a pile of gravel should work, but I'm still surprised when they actually do.

After shovelling 3/4 of the gravel into my grow bed, I got lazy and went to bed. But I thought I'd try getting a head start to cycling up my system as gravel in a grow bed, and a pile of gravel on the ground. 

It was about to rain, so I figured it was a good time to add some fish emulsion to the gravel. When I last wrote about pump-less cycling, I promised I'd let you know if it worked.

It worked!

My recent test showed some nitrites.

The sample pictured was taken from rain runoff, at the standpipe in my new growbed.

To make sure I wasn't getting the nitrites from the bottle of fish emulsion, I tested some fresh water with fish emulsion added. 

ammonia 2.0

nitrite 0.0

nitrate 0.0

What this means is, there were no nitrites introduced directly from the bottle of fish emulsion. What that means is that my pump-less, sump-less, no fishtanked system is cycling, because the nitrites must have come from the bacteria in my new system.

No great surprise really, but still interesting.

It's actually not that important for me to cycle my system, because I will be adding 100 litres of mature media from my test system. That 100 litres of media is currently coping with my eleven silver perch, so in the new system, it should continue to cope. As long as I transfer it in such a way as to keep it wet at all times, my nitrifying bacteria colony should find its new home welcoming. I'm told I should bury my old mature media from the small test system at about half way down into the new gravel media for best results.

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.