Urea

If you visit my blog on a regular basis you have probably come to realize I don't just accept what I have heard on the internet.   I was told that I should be cautious about using Urea because it will continue to transform into Ammonia over time and that I might create an Ammonia time bomb.  The reasoning was that the Ammonia I measured one day may continue to increase due to previous applications weeks before, and I might find my Ammonia levels on a fast track to disaster.

I have also been adding fresh urine which I was told would act the same way.  So I did a test
On Sept 6th I mixed a 1% Ammonia solution using Urea.  One week later I saw no appreciable difference.  Today 14 days later I found the Ammonia level to be 4%.  So I now believe that Urea will continue to create Ammonia over time.

Urea test in back on left / System water test on right.

But I have been using Urine and Urea for several months now and my tests have never had the Ammonia 'Time Bomb' happen.   It may be that the levels I'm adding everyday are exactly what is being converted to Nitrite.

My conclusion is that Urea and possibly urine will continue to create Ammonia, but I don't see this as a reason to age the solution before adding it to a functioning aquaponic system.   But killing pathogens which even though they are not very likely to be present is a good reason.   The proper way to use urine is to store it in a sealed container for about six months.  As it ferments and turns urea to ammonia the pathogens will die. This process is described in this article   http://www.goveganic.net/article217.html

I have also been asked why I felt it necessary to add Ammonia to an aquaponic system.  That after all is what the fish are for and it seems to many that it would be detrimental to the fish. I don't believe it is if the Nitrification process is converting all the Ammonia.  I add the Ammonia because I'm still growing my fish population and the fish load is currently not supplying adequate Nitrate for the plants.

Veering off topic I would also like to add this:
Balancing the fish load hence the food loading of the system is an important topic which I will cover one day. But in short, media beds will supply a much better condition for Nitrification than a raft system while also supplying a place to grow at the same time.  I personally like rafts better, and therefore condone the use of moving bed filters which to many seems to circumvent the purpose of aquaponics.  It's just another hybrid system that when compared to media beds (also considered hybrid) provides both clean water to the fish and Nitrate to the plants.  The only disadvantage I see is that a solids filter is also required.  Otherwise the roots will become dirty and suffer from a lack of oxygen..

UPDATE: 12/23/2012
I have come to appreciate the simplicity of a media bed. Besides offering nitrification a 3/4" gravel bed will filter solids which would otherwise cling to the roots of plants in the rafts.  As my fish population and their overall size grew so did the sludge.   Cleaning my filters became an overwhelming choir. For more see Filtering Poo with Continous Flow Media Bed

Fluidized Moving Bed Experiments

I was eagerly running the tests below when I started to explain my reasons for looking outside of conventional aquaponic methods to Rob Nash who questioned my reasoning. While writing I came full circle and saw that he was right. It comes down to adding more media beds not creating a great bio filter without plants 

I've been saying it's all about the Nitrates and began to see that as my primary goal. I kinda got off track, and lost focus from the real goal which is to provide Nitrates to as much high density growing space as possible.

I've got to quit thinking like an aquarium owner and more like a farmer. .But Moving Bed Filters have the place in aquariums and aquaculture.  I ended up using the test bottle in my aquarium as a vibration filter and I created this post anyhow since it might help someone else either avoid the derailed course I had set.

It might spark an idea that willl lead to a low cost replacement to the expensive alternatives.

Evaluation of Alternative Moving Bed Media 

 

This was my first test using pumice.  

Second test using climbing rope

Third test using a variety of media

This is my vibration filter. This 40 gallon tank needed a little more bio filtration. 

This bottle was left over from the moving bed media experiments and worked well.
It's a little too tall to place it in my sump, so it's in the aquarium.  
I got the basic idea for a vibration filter from TYNE VALLEY AQUATICS, but I added an air line to give it full aeration and a bit more shake.


Here's a design that looks promising

After Life: The Science Of Decay (BBC Documentary)

Swimming With The Fish

I hope to set up a small pool this summer.  I would like to incorporate what I've learned about water chemistry and create a natural swimming pool with plants and fish rather than chlorine or salt.

Click Here for a Slideshow of Beautiful Natural Pools

Here is one of my favorite videos

Here's a report about the added value to a home with a pool. Notice the 1000 to 2000 square foot range.

Go Figure

Keeping a log

Keeping a record of your water chemistry and environment can help you understand the cause of any problems you may have later.

Here is a spreadsheet that I use to record my data.

You may choose to take samples less often, but since my system is still new I feel that every day is best for me.

Edit as you see fit.

This is an Open Office Spread Sheet.   (Please support Open Source programing and information.)

Click Here for ODS file

Activated Carbon Filters

How does a carbon filter benefits an aquarium?

Activated Carbon is amazing!  The surface area is enormous and this allows bacteria to grow much faster and more dense.  Just as we choose a porous rock for our grow beds (bio filters), activated carbon is  an ideal surface for bacteria. It's not all good because activated carbon can also grow bad bacteria that is not beneficial to our systems, but with proper care, and aeration we can avoid many of these harmful bacteria

Depending on the ionization of the carbon it also has the ability to capture a lot of impurities. For example most activated carbon filters are very good at neutralizing chlorine.

Activated carbon filters will not remove microbes, salts or nitrites, but most organic chemicals have large molecules and due to the pore size of activated carbon many of the impurities we wish to avoid are converted in the activated carbon filter.

This is how it works in an aquarium, but in an aquaponic system the goal is to utilize as much grow space as possible.   3/4" media has been proven to work best.   There are many choices of 3/4" media and I tend not  to enjoy running my hands through crushed rock. I have found smooth rock works just fine.  But recently there is a new idea being used called Bio-Char.

I love bacteria!

Yeah!
It's been 21 days since I started cycling the system.  Overnight the Nitrite levels fell to an acceptable level..

It's simply amazing to see the results of a Nitrospira bloom.

Just 12 hours ago this test was still off the chart purple.

It always seems to take about three weeks to get the bloom, but here are a few things I did to hasten the process.

• Gravel from the existing Koi pond was used in the grow bed, but it's been cold and may not have had an active culture.
• One small bottle of NiteOut was added at the beginning.  To be fair they suggest much more.
• Aqua Gold was also added on the first day.
• During the past two days I have been adding water from my aquarium, and even rinsed that bio filter in the water.
• Limited the draining of the grow bed to half way (may not have been the best thing to do)

My take on the actions above are that the commercial additives quickly promote ammonia conversion, with bacteria and enzymes, but the Nitrite conversion takes time.  My feeling is that Nitrite will always take about three weeks with or without the commercial additives.

For many years the bacteria responsible for ammonia conversion were thought to be Nitrasomonas species, but more recent research indicates that these bacteria may do little or nothing in freshwater, and that bacteria known as Nitrosococcus may be the true ammonia-oxidisers.
NiteOut claims to contain select strains of Nitrosomonas, Nitrospira and Nitrobacter.

• Nitrosomonas oxidize ammonia to nitrite
• Nitrobacter and Nitrospira oxidize nitrite to nitrate

It was originally thought to be Nitrobacter species which were responsible for nitrite conversion to nitrate, but again, recent research (by Dr. Timothy Hovanec and others) indicates a different group of bacteria - Nitrospira - are responsible, but NiteOut includes both.


I added eight of the largest fish into the 800 gallon tank today!