Category Archives: Aguaponics

Chloramine and Me

Tap WaterHere in the U.S. we’re used to the idea of turning on the faucet and having unlimited quantities of clean, safe drinking water available at all times. We should definitely count our blessings. In some parts of the world people have to walk for miles each day to fetch water, water that we probably wouldn’t consider safe to drink. But it’s what they have.

Even in the United States our tap water isn’t completely pure. The Environmental Protection Agency (EPA) has rules regulating contaminants in water. Testing and compliance however is almost completely in the hands of our local utilities. If you have any concerns about your local water supply it is up to you to check up on it. If your local water utility exceeds the EPA guidelines for contaminants it is only required to inform you, by mail, within thirty days after they discover the problem. If they don’t test very often, who knows how long that might take. According to the EPA,

In 2001, one out of every four community water systems did not conduct testing or report the results for all of the monitoring required to verify the safety of their drinking water.

There are many resources on the web that discuss the various contaminants in drinking water and their possible effects on human health. I won’t go into that here. I want to concentrate on what we might find in our tap water that will have an effect on our ability to raise food.

The only water contaminants that I’m seriously concerned about in my garden are chlorine, Cl2, and sodium, Na. The EPA allows utilities to add a maximum of 4 ppm of chlorine to drinking water as a disinfectant. Now, I have no problem with that. The alternative to adding chlorine is to allow unchecked bacterial growth in the water mains. This could lead to bad results!

There are two problems with chlorine once it reaches my garden.

First, it will continue to do what it’s designed to do – kill microbes. Why is this a problem? My compost piles, the bacteria in my aquaponics water, and the microbes in my soil are major parts of my garden’s ecology. This ecology is necessary to grow high quality food.

Secondly, it is poisonous to my fish.

Back in the old days we had a simple fix for this problem. To prepare tap water for adding to an aquarium or our turtle pond my mom would fill up a suitably sized container with tap water and let it sit, uncovered, for two days. Virtually all of the chlorine in the water would simply evaporate into the air. Then it could be added without any worries about killing our aquatic creatures.

When I first started my tabletop aquaponics unit this is what I did. And boy did I have trouble. It turns out that elemental chlorine is no longer the preferred disinfectant in Pinellas county. These days the water utility is using chloramine as the disinfectant. Chloramine, a chlorine compound, is not as effective a disinfectant as straight chlorine. It is, however, more stable. It ensures that the water is delivered to all households still containing enough residual chlorine to protect from bacterial growth. It also does not react as easily with chemicals in the pipes. The EPA found that chlorine on its way to my house could form some very interesting molecules—carcinogens.

As an interesting aside, chloramine is formed by first chlorinating the water and then adding ammonia. Your mom was right when she warned you not to mix ammonia and bleach!

Once again, the problem with chloramine is that it does what it’s supposed to do. It remains stable. If you fill a bucket with tap water and let it sit for two days the chloramine does not evaporate. It is still present, ready to kill any fish or microbes it touches.

Sodium ThiosulphateAfter learning this I surfed aquarium websites to discover a solution. Many aquarists use a chemical called sodium thiosulphate  to neutralize chlorine and chloramine. I began to do likewise.

Warning: on a couple of aquarium forums I found references to using chloramine to help prevent or cure diseases of freshwater fish. The writers were confusing chloramine with chloramine T, a very different molecule that acts as both a mild disinfectant and as a sulfa drug. This may be used (with approval) for treating diseases. Normal chloramine isn’t good for fish.

Once I moved into my house, however, I began to have my doubts. Is this chemical an acceptable one for organic gardening? What about the fact that it neutralizes the chlorine by turning it into sodium chloride – salt? Sodium, it turns out, was something I was adding to the water. Salt isn’t good for plants.

I wasn’t the only person wondering about this. Shortly thereafter received Friendly Aquaponics newsletter #125 talking about the neutralization of chloramine. I did a little research and, by the time I had received newsletter #126 I’d found the same answer that Suzanne came up with. It was reassuring to have her validate my research.

As I go to press 🙂 newsletters 125 and 126 are not yet available online. The bottom line, however, is that vitamin C, ascorbic acid, neutralizes chlorine (including chloramine) . And ascorbic acid is on the list of chemicals that may be used with organic fruits and vegetables .

Since I’m only concerned with my backyard, that’s good enough for me. If I were trying to get organic certification I would do a lot more research!

Remember how sodium thiosulfate neutralizes the chlorine? It turns into a chloride, specifically sodium chloride, salt. There is a form of vitamin C called sodium ascorbate. Don’t use this—it also converts the chlorine into salt. The sodium-type chlorine neutralizers are popular because they work almost instantly—and salt has no effect on the pH of the water. A small amount of salt in the water doesn’t harm most fish—it may be beneficial for certain species. Remember, though, that salt isn’t good for any plants commonly grown for food.

Ascorbic acid works similarly in that it converts the chlorine into a chloride. The chloride in this case, however, is hydrogen chloride. Another name for hydrogen chloride dissolved in water is hydrochloric acid. What? Are you nuts, Rick? You’re worried about a little salt so you decide to poison your fish and plants with hydrochloric acid?

I agree that HCl isn’t a recommended additive for aquaponic water. It can, however, be easily neutralized in one of two ways. The fast way is to stir a calcium carbonate slurry into the water. Calcium carbonate, in the form of crushed oyster shell or crushed coral, is an approved substance for organic farming. In fact, I add it to my tabletop aquaponics unit to buffer the pH. The Friendlies use it for the same purpose. This converts the HCl to calcium chloride, carbon dioxide, and water.

The second way to get rid of the HCl is to wait. Almost all of it will evaporate in two days—just like chlorine.

How much ascorbic acid do I need to add to my water? That depends upon how many parts per million of chlorine it contains. Pinellas county aims to deliver 2 ppm to my faucet, but my tap water has a very strong chlorine smell. I like to play it safe and assume I’m getting 4 ppm. At that concentration I need to add 1 g of ascorbic acid to every 25 gallons of water. If I overdose on ascorbic acid it won’t really matter. Heat, sunlight, and oxygen (air) destroy it very quickly. Since I let the water sit in order to evaporate the HCl, the ascorbic acid will degrade at the same time.

MixingAscorbic acid can be purchased in bulk from many online retailers. A 1 pound bottle contains about 454 grams, which would be enough to treat 11,350 gallons of water. At $20 per pound, it will cost me $0.0018 per gallon. Maybe I should buy a smaller bottle.

The method I use for dosing with vitamin C is to dissolve a quarter teaspoon (about 1.25 g) in 6 tablespoons of water (3 ounces). Then I use one tablespoon of the solution in a five-gallon bucket of water. I store any unused portion in a glass bottle in the refrigerator. That way it doesn’t degrade so quickly.

God bless you all,


Tabletop Aquaponics

Both of my regular readers have wondered why this blog is called “The Working Fish.” Wonder no more! All will be revealed.

I have always, as you might have gathered, been interested in gardening. When I was but a young lad I began vegetable gardening—ostensibly to help feed my large family. In truth, I just love getting my hands in the dirt. Another of my lifelong hobbies is reading. I saw no reason not to combine the two and read everything I could get my hands on about gardening. There are so many different techniques to try!

One of my first gardening experiments was to emulate a technique that the Indians taught the Pilgrims—burying fish under hills of corn. It makes sense—fish is very high in protein which is high in nitrogen of which corn requires a lot to grow well. Providentially, one neighbor was an avid flounder fisherman who would often share his excess catch. Sometimes his gift would literally fill a bushel basket.

Even a good Roman Catholic family – a family of ten – could eat only so many fish. My dad gave me permission to experiment with the surplus. I carefully dug holes in our rocky soil to plant each fish before mounding up a hill of earth. I buried the seeds at the exact depth specified on the packet and watered them thoroughly. My excitement was palpable. I had never shot a deer with my bow and arrows but I could live like an Indian just the same!

The next morning I rushed out to inspect my handiwork. I was chagrined to discover a garden full of craters—one in place of each of the carefully prepared hills. During the night the neighborhood cats had descended to dig up the banquet I had so thoughtfully prepared. That afternoon, after school, I replanted my corn – without fish. The New England Indians must not have had house cats. Perhaps the squaws sat up all night guarding their fields?

As a teenager I continued to read and experiment. A favorite author (and not too distant neighbor) was Ruth Stout. Her book, Gardening Without Work, was one of my favorites and I became a fan of sheet composting. This gave me more time for reading. I plowed through Plowman’s Folly, had a good time with Living the Good Life, longed for more land while reading Five Acres and Independence, and spent  forever with Farmers of Forty Centuries.

In later years (I’m skipping over a lot) I successfully experimented with the ideas in The Self-Sufficient Gardener  and The New Square Foot Gardening. I learned from experience that every technique has its advantages and disadvantages. After moving into an apartment I had to do my gardening on borrowed land – I was using both the raised bed/sheet composting and square foot styles, depending on the crop. Are you getting the idea that this is something of an obsession with me?

Tabletop1Then, if memory serves, I ran across an article, “Food Storage Program for Paleo Dieters” by Cathy Cuthbert on Lew Rockwell’s webpage (which I read every day). This article mentioned a type of gardening I’d never heard of before – aquaponics – and contained a link to the webpage of Friendly Aquaponics. I clicked. I ordered the microsystem plans. Within weeks I had one of their tabletop systems up and running in my apartment.

Friendly Aquaponics doesn’t sell kits—they sell instructions. My tabletop unit includes a Rubbermaid tote from Walmart; a mud tub and a waterfall pump from Home Depot; and an air pump from PetsMart. The mosquitofish were 12 for a dollar at a local pet store.

Fish1I learned a lot—especially what not to do. Some lessons were: Feeder goldfish are not as tough as they look; chloramine in tap water doesn’t simply evaporate like chlorine; it’s tough to fit adequate grow lights on a tiny table in a tiny apartment. But, who cares? I knew I’d be out of there in a few months!

My intention was to gain a little experience with the tabletop unit in preparation for buying a house in 2011. Then, with my own yard, I would be able to put in a larger system and do some serious experimentation. Unfortunately the house and yard I Tabletop2was looking for exactly matched the sort that investors were buying as rental properties. It took me till this year to a) find a suitable property and b) not get outbid by a cash investor. So here we are.

As you can see from the pictures my tabletop unit moved to the new house with me and is now sitting on my patio. The fish and basil plants seem quite happy in their new home. I will finally, on this long holiday weekend, be able to start assembling my microsystem from a pile of painted lumber.

I have now come full circle and will, once again, be fertilizing my vegetables with fish.

Check back for updates,