Monday, November 26, 2012

Filtering Poo with Continous Flow Media Bed

My indoor system started out with a gravel bed. After repairing a leak in the 45 mil EPDM liner of that grow bed, I decided to go with a Deep Water Culture (DWC) raft.  With only one 10' wall glazed my grow bed is 30"x10' long which is a rather small 25 sq ft..  I found it easier to utilize that precious space with a  raft system.
A panoramic view inside grow room.  800 gal fish tank on left grow bed on right

But loosing the large media bed meant that I would also lose the filtering capability of the 3/4" rock media.   So I decided to build a filter using evaporative cooler pads.   This works great at first, but after a few months the fish population began to grow and the fish got bigger.   The filter could no longer keep up with the poo.   Cleaning filters everyday was more work than I was willing to do.

So I decided to return part of the bed to a gravel media, and keep the rest as a DWC grow tank.

The DWC tank with gravel to the right of a plastic fence partition
I built a partition out of plastic fencing and PVC pipe.  Filled one side with 3/4" gravel and extended the return water pipe from the fish tank so that it dumps on top of the gravel.   One thing I'd like to say about that is I also used 2" pipe rather than 1-1/4" because the smaller pipe tends to clog.

At this point I began to have concerns about a continuous flood gravel bed.  RupertofOZ was kind enough to dispel my fears by pointing me toward a very good experiment done by  


Cleaning New Gravel and Pipe Size

Cleaning Gravel:

Yesterday I cleaned about 5 cubic feet of new gravel.  In the past I have used progressive tubs and a bucket filled with holes.  I would start at one end and work my way down three or four barrels of progressively cleaner water.  This proved to be insufficient and the barrels became quite dirty very quickly which meant that I would constantly have to start over with more clean water.

But yesterday I used a small cement mixer.  I'd put 10 shovel fulls of gravel in and filled it with water.  Then turn the mixer on for 15 seconds, and dump the water.  I did do this about 7 or 8 times until the water was running clear.

This next step may not be necessary, but then I did a final rinse in a white bucket.  I was able to easily see how clean the water was in the white bucket, and two quick rinses generally finished the job.

It took a few hours to perform this cleaning, but after several bad experiences with cloudy water, I'm very happy with the results.  Today my water is perfectly clear.  

Pipe Size:

A couple months ago I added 10 feet of 1-1/4" pipe to the line from my fish tank to the grow bed.  It has worked well until recently when I noticed that the water in the fish tank was beginning to raise.  Closer inspection of the pipe revealed that gunk had built up on the surface and was slowing the water down.   I replaced the pipe with a clean 2" pipe.   I'll let you know in a few months how that worked out.   I'm feeling confident that this is going to work out much better.    As a general rule I'd say 2" or larger pipe should be used everywhere.

Friday, November 23, 2012

System Tours

 These are some system tours I like.

Rob Torcellini's Videos

Rob is a perfectionist and an artistic builder.  With 50 videos and counting he has documented one of the most beautiful garden rooms ever built.  His design is well thought out and includes one of my favorite videos about the Rocket Mass Stove he built to heat his aquaponic sanctuary.
Aloha Mahi'ai Aquaponics

Important issues such as aeration, and power consumption are discussed in this video.  The FaceBook page above is alive with many more systems from around the world.

Near the end of this video the aeration system is shown.  It works by creating a strong vortex which draws air down into the water as it exits into the fish tank.

Larry Reinhardt 's Videos

Larry is not focused on Aquaponics and these videos could be better, but he has built two impressive aquaculture systems in his backyard.   I liked these videos because he uses nothing but air to pump the water in his 3000 gallon system and has a very simple filtration system which he calls the manure chamber.  It requires very little time to clean.

Larry shows his filter system

A tour of  Larry's Aquaculture System
He briefly shows construction of his plywood tanks

Saturday, November 17, 2012

Free Form Concrete

I'm experimenting with RapidSet Cement ALL.  I soaked this cloth in a slurry of this rapid setting cement to create a hard free form surface.  I'm thinking this might be fun to use for free form sculpture and architecture.   I envision being able to make everything from flower pots to actual structures or garden art.  Possibly layering this over foam insulation to create light weight structures..

Taking that idea one step further a layer of expanding foam could be applied to this cloth and then covered once again with cement soaked cloth to create a very durable light weight insulated wall.  Larger structures could be created this way by draping the first layer over a tent, balloon, straw or even a few ropes to create the initial shape.

What a fun way to make a play house, or garden shed

Thursday, November 15, 2012


Last week I wrote about Mike McGroarty.  
If you were inspired by Mike's videos you will surely find Grow'em Plant Progagation Database  useful.  

This is a database containing instructions on propagation technique for of over a thousand plants 

Many trees do not reproduce the same fruit as the parent plant.  You can take a gamble and plant a lot of seeds, and then hope for something good, or you can clone the parent with a graft.  This database will indicate whether the plant should be propagated by seed, graft, division or other methods.
This image is from Australian Native Plant Society

Equipped for Success!

Here are a few special tools, pieces of equipment and ideas that may contribute to your aquaponic gardening success.

Total Dissolved Solids meter
Bluelab Commercial Truncheon® Meter
This is a Total Dissolved Solids meter.
Total Dissolved Solids concentration has a direct effect on plant growth rates.

When asked "How do you measure total dissolved solids?"   Dr. George B. Brooks, Jr. said 
Couple of ways. I use one of these for example:
Or you can measure it by how well the water conducts electricity since it is mostly the sodium, calcium and magnesium salts that cause the problems:
Some suggest that measuring EC is more accurate and give you a better measure of how salts are affecting your plants.

Before shopping for a TDS or Salinity Meter read these

Dissolved Oxygen Meter 
These are one of the most valuable instruments you can own if you are stocking in high density. I believe there are two types of DO Meters.   I've been told profession aquaculturist  generally do not use the type with a membrane.  But DO Meters can be very expensive and any good meter is probably better than none at all.
I will have to do more research and add to this post as I learn more.

Ceramic Metal Halide 
Ceramic Metal Halide bulbs are efficient and the full spectrum of light is as close to the Sun's spectrum as you can get.  
Supplemental lighting will permit you to grow 365 days a year. 
Remember to wear shades and sun block!  CMH really are FULL spectrum.
I ordered mine from

This is a High Pressure Sodium (HPS) replacement bulb.  The important thing to know about the ballast is that it should be a Copper Core HPS ballast.  I also bought my ballast kit for about $69.00 from the same company Advanced Tech Lighting.

Rocket Mass Stove
Efficiency is the key to heating a green house.  Check out thess videos about Rocket Mass Stoves

Add a self feed bin for pellets!

Greenhouse Glazing

Greenhouse plastics can diffuse light and transmit as much as 90%  of the Sun's light
Agricultural Solutions - Polyethylene Greenhouse Films
Interstate Plastics - Polycarbonate twinwall

Speaking of greenhouses, here are a few ideas

Something as simple as this canopy frame could be used for a basic frame with a greenhouse film.

 Or you can go a little bit better with a FarmTek greenhouse

 My ideal green house would be partially bermed in with a massive wall on the North side and glazing  on the South side.   Energy conservation is key to making a greenhouse work.  Here are some examples.


Wednesday, November 14, 2012

Don't waste those pits!

Do you ever think about planting the pits from avocados or other fruit?
Here's a link with more information.
Beware many fruits do not reproduce the same results from seed.
You may have to graft!

Thursday, November 8, 2012


Water is becoming a scarce commodity.  Aquaponics is one way to grow with less water.
Here is a another brilliant alternative for dirt based farming.

Michael Pilarski's Food Forest - Closed Canopy Gardening

I love the enthusiasm and wild variety of plants Michael shows us in his food forest

Wednesday, November 7, 2012

Permies Blog

Here's a blog I found today while researching Rocket Mass Stoves.   I liked it and thought you might too.  Permies.Com
Paul Wheaton has put a lot of work into finding the most creative yet practical methods of living well, and leaving a small foot print.
I highly recommend watching his many videos which are often conducted like an interview to extract the most valuable information.  He does a wonderful job of editing and creates inspiring documentaries on a wide range of topics helping to create a better world.

Monday, November 5, 2012

Seed Savers

Here's a link to Seed Savers.   David Chrstoph was kind enough to link me to this great resource on my othe blog Fibonacci-Financial.

Thursday, November 1, 2012

Mike McGroarty

This is not really aquaponics, but I've been following Mike McGroarty for years.  He is a treasure trove of information about how to make money gardening on a residential sized lot by cloning plants .   He holds plant sales in his front yard, and brings in a lot of cash doing what he loves to do.

I believe many of us feel the same way about aquaponics.  These Emerald Green Arborvitae
will only grow about 6" per year and take up a fair amount of real estate, which is why these bushes fetch a handsome price, but it's Mikes ideas like this that continually inspire me to work towards my goal to produce a product I can sell. 

You too may wish to subscribe to Mikes newsletters and videos.

Here are all of Mikes Videos