Backyard Aquaponics
A place to discuss aquaponics

No question that copper in enough concentration will kill fish. But for the general information of this forum, I did not know that when the tank for my system was poured (concrete). The contractor that poured it recommended copper for the 24 lines I wanted run through the wall (16: 1" & 8: 3/4") and that is what was done. Each one is 12" long. That is a lot of copper. I ran the system 18 months and harvested my fish. Because I found info on copper at this forum and elsewhere, I was very concerned. All during that 18 months I used a copper test kit and got negligible readings. I would now conclude that copper from pipes does not easily transfer to the water. I read someones comment here that they stopped using copper for hot water in house construction because of its toxicity. Is it toxicity or cost that caused the move to CPVC? We have used lead soldered pipes, galvanized pipes, copper pipes, and plastic pipes in our homes. Does anyone have a link to see real study on toxicity for household water in each case? I have been exposed to all of them in my lifetime and most other people have also (millions). How much damage resulted? Is it safe if water is used every day (therefore flushing water through before it sits in the pipes long)? Perhaps the solution in older homes is to flush some water through before use if the system has not been running much water through for a time? With laudry and toilets, most houses keep pipes pretty well flushed.

Anyway, I wanted to share that my system showed negligible copper (by test kit) with a lot of copper fittings over an 18 months period of water recirculation. Just thought you might be interested, if you are worried about a small copper fitting or two in your system. Now my system was at a pH of 8, perhaps it would have been different at 6.5?

Anyone else have tested copper or other experiences

The high ph would of slowed or stopped the copper from getting into the water. Same thing with water pipes in your home. Plus water in the house is open looped. As most AP systems tend to be acidic metals will disolve and mix with the water. Your system might be okay but over time if the ph lowers it could end up a problem.
Thanks for the information.

pH definitely has a huge impact on the toxicity of zinc and copper. Since you were having too high pH problems with your system, that probably explains why very little copper was getting into the system. If you solve your pH problem, you might find the copper becomes more of an issue.

Another member has done tests on the galvanized rain water tank and found that huge amounts of zinc were getting into the water. Since roofing and galvanized rain water tanks are being exposed to water with a lower pH, this probably explains why that water was a problem.

What are the "lines" that are run trough the concrete Doug????

Do they carry water from your system?

Are they actually exposed to the AP water?

Rupe,
At 12 inches each they probably "Pierce" the tank, then connect to pipes to carry water to and from GB's etc.


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What gets lost in a lot of these conversation is what is actually being talked about.
To describe the pipe as "copper" is somewhat innacurate ,, it is copper COATED in copper oxide,,,I'm not a chemical engineer but you get what I mean.
To put it in another context ,, aluminium is often used for manufacture of windows frames because it is a non reactive, stable and doe not corrode easily ..... well Thats is absolute BULL ,, Aluminium is actually VERY reactive ,, but is reacts on contact to weather into Aluminium oxide ,, so the coating of this Aluminium oxide is what actually makes those Aluminium windows so good.the problems occure whenthe oxided material are constantly striped away ,, if you removed the Aluminium oxide from your window frames by scrubbibg , they would be gone in a matter of days if not hours, perhaps minutes.
Copper is quite reactive and definately DEADLy especially to crustaceans.definately worth NOT having the risk of copper contamination in any system ,, if the copper is un-avoidably there ,, best it's oxide coating not be disturbed ..... friction , and acidic condition will be the
enemy.

The pipes are used for circulation to/from Grow Beds, connection between tanks, and filters. I also have a heat exchanger made of 3/4" copper pipe (20'), but that has a coating that prevents contact with water. I will now find if lower pH will cause more of a problem. My tank now has Permaflex urethane coating and I will have pH below 7 during the next grow out (starting May 9, 2009 and ending Sept 2010). I will be running a copper test each month.

In fact you are correct about the copper forming an oxide (tarnish). I also consider the possibility that microbes will ingest copper from the pipes and then being eaten by fish for another mode of transfer of copper to fish. All I can do is test for copper with a test kit. The better evaluation would be to test the fish flesh for copper content at harvest or for any fish that dies in the system. I am not funded for such, though. Will the lower pH cause the copper to form more soluable compounds? The copper tests should indicate that.

Doug,
I had problems with a 5mm copper line to the fridge in my childhood. The iceblocks were coming out with a blue tinge. Dunno if this was dangerous, but it's why that line was change to plastic. The rest of the house remained 3/4" copper.

There is one other way to deal with the copper. As the copper reacts, ions leave the metal and become suspended in water. This is why it becomes a problem, as your pipes degrade and your water pollutes.
If you find your pipes are being eaten, you could put a small charge, say equivalent to a AA battery onto the pipes.
If you attach the positive to the pipe, and the negative to the water, then electrons will flow from the negative to the positive, if your water is saturated with ions, this will in fact cause your pipes to grow with enough voltage, however just a little will stop the corrosion.
Be aware that the metal exposed to water on the negative side will corrode, lots. Perhaps iron might be something to try, I don't know if it would be the same as chelated iron...

Now that is an excellant idea. I can connect all my copper together outside the tanks. An iron electrode can only do good as the sacrificial element. I will use the 13 volts already there from my battery backup system. By spacing the iron away from the copper I will not be overdoing it. I will measure the current and keep it down to a few microamps. Again, great idea.

You can get some nice tank boss, why not rip out the copper and replace with plastic. A picture might help also, if its not possable to remove and replace.

Concreted into the tank wall, I feel he will not want to remove them.

Hammer and a drift.

"can" and "want" in this situation may not be equable. I'd hate to make a brand new tank ugly if I didn't have to.

Just had a quick look at the pictures. Nice tank.
The copper does not look like it would take a lot to replace. Just hammer it out and slip in a plastic pipe with some glue. If the water level does not cover the pipes you could use a smaller pipe to go through the copper. The heat exchange might be a different story but I didn't read if it used system water or not. If it has its own water then all the pipes need is paint when in contact with the water.