Copper and fish

[M Cosmo]

I want to add a heater to my fish tank and it has a small temp sensor. Here is a pic.

It is about 4 inches long. Will this small amount of copper poison my fish. I have about 600 gallons or more of water in the system.

Ron is using the same heater and he encapsulated his in a bottle and sealed it.

I was thinking of just painting mine with some clear since it won't be hotter than 80 in the tank.

[TCLynx]

Well, I know of several situations where people have used water collected in galvanized rain water tanks and/or off galvanized roofing and it seem the water when tested was too high in zinc to be thought safe as drinking water. Problem here might have to do with rain being slightly acidic and thus leaching more zinc than higher pH water would.

As far as water coming into the house in copper or galvanized piping. At my house the well water comes up a 126 foot galvanized pipe before it goes into the plastic piping and then in the house there is some copper at the water heater. I figure I've not had fish deaths due to these metals because my well water is highly carbonate buffered as it goes through these pipes and it only goes through these pipes the one time before going into the AP system which is mostly free of metals in water contact.

Another point to keep in mind is some types of fish are far more sensitive to copper and zinc than others are. Tilapia seem to be a tough fish.

There are people out there who have struggled with dieing fish because they used galvanized stock tanks as fish tanks or grow beds.

How quickly would a temperature probe cause issues in a tank? That would totally depend on the pH and amount of salt in the system but I would worry even more about what might be under the copper that could be even worse for the food system.

Most commercial fish feeds do have some amounts of metals in them too because as we know some amount of zinc and copper are necessary. I would not want to add much extra beyond what is already in the feed.

If using water off of galvanized roofing or from a galvanized rain water tank, I would probably run some periodic zinc tests just to know what sort of levels are in the system.

[RupertofOZ]

Kobus, I'll get back with a more detailed reply tomorrow.. with some links for you that address some of your points... it's late over here

IMO... there is just no doubting the toxicity of copper to fish and crustaceans... and a long list of studies support that believe....

Rainbow Trout are known to be acutely suseptible, and channel catfish aren't far behind.... googling should bring up many studies....

Fish feeds have been formulated accordingly for dietry requirements, without toxic effects....

There are recommended "daily dietry intakes" set by WHO for humans, both adults and children... and levels set for baby formulas...

Likewise there are levels set by the US EPA.. and other simil;ar bodies...for "first draw" levels in drinking water...

There has been considerable research done regarding the necessary trace element requirements for plant growth... particularly with regards to hydroponic nutrient mixes... and levels set accordingly...

And in all cases the levels are remarkedly similar... and reflect very closely the levels found in natural "water" systems...

Cases of copper, zinc, molybdemum and boron deficiencies in plants... are extremely rare... and alwyas related to specific soil/geological conditions... or soil depletion from extensive agriculture...

More tomorrow...

And our aquaponic systems, by nature of their inherent temperature, pH ranges and carbonate buffering levels... are condusive to providing "motile" soluble metallic ions... adding a lump of copper into a system is a danger...

Kobus Jooste said:

For me there is a big difference in water runing off a roof, touching it for maybe seconds, and that heater suspended in the water for a long time. That is why I said I would have an issue with that heater's shield in the water - way different to a roof scenario. I'll delve deeper, but have people looked at the amount of zinc plants can take up? It is far more than the copper. Did people see the bit that says in an absence of Zinc, plant crops are notably smaller? Do people without the faintest geology knowledge know what is potentially in volcanic or igneous rock? Do people without a knowledge of human physiology know that you basically have to drink a batch of copper sulfide to show sighs of copper toxicity due to the abilities of our excretory system?

Past posts of mine got elaborated on by people that "wanted people just starting up to know the basics". So here is my elaboration. Copper and Zinc is required in a system, and I do not support random hysteria on the topic. I completed post-graduate courses on Ecotoxicology thus am not being flippant or ignorant. I also happened to major in geology so I know how common metals are in rock and thus also in the water that flowed through it. Please supply tox values for high Copper and Zinc for plants, fish and humans, as in many parts of the world, people have copper pipes for water and steel roofs from which water is collected, or have it coming in from soil and rock influencing ground water.

The equation will look like this: Metal input - plant requirements - fish requirements = surplus in the system. Surplus above X = toxic to bacteria, worms, fish or plants. Levels above Y cannot be safely flushed from your system and poses a potential risk to your health. Does metals in solution precipitate out in systems with basic pH and high buffering capacity? People keep on posting about acidic unbuffered water but fail to state what this all means for an AP system around 7 with a lot of buffer in it. Details please!

>

[Harold Sukhbir]

Hi Rupert.
"Fish feeds have been formulated accordingly for dietry requirements, without toxic effects...."

I don't think these formulas were developed for a wide variety of fish species, mostly for Trout and a few others.These were done specifically for Aquaculture farming, Water is exchanged and changed and metal concentration remain within safety levels according to the FDA per batch of fish and little is know of the build up of metals in an Aquaponic environment where the system water remains closed. As you know,waterbourne and dietbourne transfer of metals have different effects on different fish. I agree with Kobus that metals are necessary building blocks for fish but it's necessary to establish data on metal inputs and their assimilation on our fish. Some species are more tolerant of certain metals and these pose the highest risk in human diet.I think studies should be,if they are not already, done on this cumulative build up of metals and transfer to various species in Aquaponic applications.From this data i think we'll be better situated to design the right feed for our fish and factor in added metal inputs.Of course you can make corrections to the preceding as necessary.

RupertofOZ said:

Kobus, I'll get back with a more detailed reply tomorrow.. with some links for you that address some of your points... it's late over here

IMO... there is just no doubting the toxicity of copper to fish and crustaceans... and a long list of studies support that believe....

Rainbow Trout are known to be acutely suseptible, and channel catfish aren't far behind.... googling should bring up many studies....

Fish feeds have been formulated accordingly for dietry requirements, without toxic effects....

There are recommended "daily dietry intakes" set by WHO for humans, both adults and children... and levels set for baby formulas...

Likewise there are levels set by the US EPA.. and other simil;ar bodies...for "first draw" levels in drinking water...

There has been considerable research done regarding the necessary trace element requirements for plant growth... particularly with regards to hydroponic nutrient mixes... and levels set accordingly...

And in all cases the levels are remarkedly similar... and reflect very closely the levels found in natural "water" systems...

Cases of copper, zinc, molybdemum and boron deficiencies in plants... are extremely rare... and alwyas related to specific soil/geological conditions... or soil depletion from extensive agriculture...

More tomorrow...

And our aquaponic systems, by nature of their inherent temperature, pH ranges and carbonate buffering levels... are condusive to providing "motile" soluble metallic ions... adding a lump of copper into a system is a danger...

Kobus Jooste said:

For me there is a big difference in water runing off a roof, touching it for maybe seconds, and that heater suspended in the water for a long time. That is why I said I would have an issue with that heater's shield in the water - way different to a roof scenario. I'll delve deeper, but have people looked at the amount of zinc plants can take up? It is far more than the copper. Did people see the bit that says in an absence of Zinc, plant crops are notably smaller? Do people without the faintest geology knowledge know what is potentially in volcanic or igneous rock? Do people without a knowledge of human physiology know that you basically have to drink a batch of copper sulfide to show sighs of copper toxicity due to the abilities of our excretory system?

Past posts of mine got elaborated on by people that "wanted people just starting up to know the basics". So here is my elaboration. Copper and Zinc is required in a system, and I do not support random hysteria on the topic. I completed post-graduate courses on Ecotoxicology thus am not being flippant or ignorant. I also happened to major in geology so I know how common metals are in rock and thus also in the water that flowed through it. Please supply tox values for high Copper and Zinc for plants, fish and humans, as in many parts of the world, people have copper pipes for water and steel roofs from which water is collected, or have it coming in from soil and rock influencing ground water.

The equation will look like this: Metal input - plant requirements - fish requirements = surplus in the system. Surplus above X = toxic to bacteria, worms, fish or plants. Levels above Y cannot be safely flushed from your system and poses a potential risk to your health. Does metals in solution precipitate out in systems with basic pH and high buffering capacity? People keep on posting about acidic unbuffered water but fail to state what this all means for an AP system around 7 with a lot of buffer in it. Details please!

>

[Jesse Hull]

Sealing the thermocouple using glass and water is a great idea. 

The correct temp wouldn't register as quickly, but there shouldn't be rapid temperature fluctuations in the tank anyway.

Ron Thompson said:

I first tried just wrapping the copper thermostat in a strip of duck tape - but it would not turn on. After looking at the directions for the unit it says the lead must be in water to work; it will turn off in air as a safety feature. So I concluded that there is some type of electrical switch that must be shorted by the water to work. Therefore I put the lead in a glass bottle, filled with water, sealed the top and submerged it the tank. The water in the bottle is isolated, so no copper issue. It is also held at the same water temp as the tank by conduction.

Michael, I would be hesitant to seal the lead with any coating due to the apparent short switch on it.

I also removed the galvanized shield as it is strictly a safety feature to keep livestock from burning their noses. The fish have not had a any issues with the bare heating element (which is stainless steel).

[Vlad Jovanovic]

Man oh man, am I glad that my galvanized steel greenhouse rain gutters are coated with tar/bitumen as I'd hoped to use them to collect rain water to top up with (I have pretty 'hard' water). I've already installed PVC down spouts and connected the down spouts with a PVC channel. Does the bitumen pose any potential leaching hazard to the fish that you know of, Rupert? (Polycyclic  aromatic hydrocarbons or whatnot?) If so, I'd like to know before I go through the hassle of digging the hole and installing the catchment tank. Thanks.

RupertofOZ said:

As an aside... it has been shown in many studies that Calcium hardness significantly affects survival of juvenile
fish exposed to a toxic concentration of copper sulfate in low alkalinity water.

But, magnesium hardness provided no protection from copper toxicity.

Note... the studies refer to low alkalinity water... low pH...

Calcium Hardness is a measure of carbonate buffering in the system....

Magnesium hardness is a measure of the mineral content of the water, usually Calcium * Magnesium... and known as general hardness, often referred to as "hard water"

Sorry Kobus... but I'm going to have to agree to disagree.... the studies relating to copper toxicity... are long and varied... and consistant...

Bare in mind that AP systems are recirculating by nature.... and almost all metals are cumulative in fish protein...

Put copper & zinc in your systems if you want... I wont!!!

[TCLynx]

Can you get the MSDS for the bitumen used?  I know some people have used Bitumen to coat tanks they used for aquaponics but you might need to research more in depth on the particular product to decide if you feel it is still safe for catching the water you will use in the system.

[Vlad Jovanovic]

Imported them from Holland second hand (along with the entire GH), but I will try. Seems like a long shot, but worth the try. I'd be so f*d if couldn't use them...I'm hoping that it would probably be (fish) safe based on some studies, particularly the one Shell Oil Research in Amsterdam which states:

Abstract

The application of bitumen in, e.g. asphalt roads, roofs and hydraulic applications will lead to the leaching of compounds from the bitumen/asphalt into the environment. Because polycyclic aromatic hydrocarbons (PAHs) are present in bitumen, static and dynamic leach tests have been performed to study the leaching behaviour of this class of compounds. Nine petroleum bitumens covering a representative range of commercially available products (my italics) and one asphalt made from one of the bitumens have been tested in a static leach test. The asphalt has been also subjected to a dynamic leach test.

The main conclusions are that a 30 h dynamic leach test is sufficient to determine the equilibrium concentration that will be reached after bitumen or asphalt has been in contact with the water for more than 3–6 days. As an alternative to performing a leach test, this concentration can be calculated from the PAH concentrations in the bitumen, and their distribution coefficients, as calculated here, or from their aqueous solubilities. The equilibrium PAH concentrations in the leach water from bitumens stay well below the surface water limits that exist in several EEC-countries and are also more than an order of magnitude lower than the current EEC limits for potable water.

But mon frere, is it fish safe? 

[TCLynx]

Well by the sounds of that, it might even be considered drinking water safe (at least based on the one class of compounds they were testing for).  Then again there are plenty of things that governments have said are food safe or potable water safe that there are plenty of people unwilling to use because of things that leach that the government didn't think to test for back when they gave it the seal of approval.

I would say, as long as you set up a roof wash so that the first flush of water coming off the roof is not collected, then your probably pretty good to go with the rain water but keep in mind that is me guessing since I've never actually used bitumen for my fish systems.

However on another note, I have heard some talk like asphalt roofs are not safe to collect rain water from, not so much because of the hydrocarbons leaching themselves but it sounded more like they were saying that pollution and pesticides and herbicides and other nasty stuff would get caught by the hydrocarbons and then when it rains they would get released into the water that was collected and therefore people shouldn't collect rain water off of asphalt roofs.  I don't know how accurate this is and I've gotten rather frustrated in my search for information about it or how one might make water collected from such safe to use anyway.  Now if you are in an area away from nasty pollution or lots of chemical spraying, it might be a non issue.

[Vlad Jovanovic]

Yeah governments have been known to do that kind of stuff for sure.

Polution? Naw...Herbicides and pesticides? Heck yes...This part of the country is all fruit  orchards, vineyards, and strawbwrries, so they do ALOT (in my book anyways) of spraying. :(  My little corner of heaven is somewhat isolated (no really nearby orchards upwind, and I have a gulley and a patch of forest between me and the nearest apple orchard, which is downwind from me), but thinking that I'd be unaffected is just wishful thinking...

The roof wash sounds like a decent precaution. Thanks.

[Jason Garvey]

Mike,

 

I've been working on a tank heater here in Oregon since returning from the Aquaponics Conference. I built my first with a copper capillary tube from a jacuzzi supply store. I'm concerned about including copper in my aquaponics system. It just isn't worth the risk to either the fish or bacteria. Also, every system variance thereafter raises the same question, "Is it the copper?". So I've been able to locate the stainless steel version. I'm meeting with some folks on Wednesday to put together a control panel for the heating element as well as some additional related components to make a much safer system. (I'm concerned that some aquapons -myself included- aren't playing safely just to save a few bucks. One of those 1500w heating elements starts to melt after about 45 seconds out of the water.) I'll keep you posted.

[Pierre Riche]

  Hi, new to this thread but had to jump in because i have two small Koi fish that have been on the verge of death for several days now. Yes! i do have copper in my system. The copper is a decorative ellement for the feed line and the return. is there anyway of counteracting the sickly effects of the copper on the fish at this point. i mean, will the fish come back to health if i add something to the water or get them into another copper free system. Any suggestions?  Thanks.

RupertofOZ said:

Every single person I know that's exposed their AP system to copper, or zinc... has ended up with dead fish... and usually within a month, or two at best...

[RupertofOZ]

It's not just the temperature that can lead to copper leaching into your water Michael...

 

But the soft nature of copper as a metal... and the acidic tendancy/trend in aquaponic systems...

 

If you need a reference to the effect of copper on fish and crustacea... bear in mind that nearly all marine anti-fouling paints are copper preparations... and nearly all have now been totally banned from marinas... as they totally destroy all marine life...