# how much copper can plants tackle?



## helenf (Mar 24, 2008)

OK, I think I've been bitten by the "NPT" bug, and I want to set one up at work. 5 gallon, lots of plants, couple of guppies. Really really low maintenance, is the plan, since I'm only in there about 4 days a week anyway. 

So I got some of the water from work and took it home to measure. Here's what I got:

- ammonia, nitrite, nitrate 0 (that much is good)
- PH less than or = 6.0 (uggh - that's much lower than my home water)
- KH less than 1
- GH less than 1
- copper 0.5ppm

Which of course raises a couple of questions:

What would you use to raise the hardness and PH? I'm considering Rift Lake conditioner, because I have it sitting around. And definitely loads of eggshell in the substrate too.

Do you think there is any chance that the plants would reduce the copper levels enough to make the water safe for fish? Or do I also need to use something to remove the copper from the water? I was reading Diana Walstad's book last night and am intrigued by the comments about plants removing toxins from water, but I don't know to what extent that works, and whether they could handle water with as much copper (let alone whatever else is in there that I can't measure).


----------



## mistergreen (Mar 3, 2007)

where are you from? where is your water from and how do you know your copper is .5ppm?


----------



## helenf (Mar 24, 2008)

I am in Melbourne, Australia. The water is the water in the lab that is next to my office at work. I work at a university, and the building in question is a fairly old (60s, I think) physics department, so a mix of labs and offices. 

I used the Seachem copper test and got 0.5ppm. I think that's fairly accurate because when I had my tap water at home tested by a water company guy, he got the same value with his complicated equipment as I got with the Seachem test, which was also about 0.5ppm. I've had copper problems before, which is why I thought to test it, and had the test for it, and why I'm wary of the stuff. The copper in my home tap water killed some of my fish.


----------



## yum (Feb 11, 2008)

5 gallons might be small enough to just use a Brita pitcher filter, you know the kind used for drinking water? I believe that will remove the copper from your water along with any chlorine.


----------



## mistergreen (Mar 3, 2007)

or better yet, get a heavy duty water filter that'll last you for a year.
And you can use it for drinking water.


----------



## dwalstad (Apr 14, 2006)

helenf said:


> Do you think there is any chance that the plants would reduce the copper levels enough to make the water safe for fish? Or do I also need to use something to remove the copper from the water? I was reading Diana Walstad's book last night and am intrigued by the comments about plants removing toxins from water, but I don't know to what extent that works, and whether they could handle water with as much copper (let alone whatever else is in there that I can't measure).


You are right to be concerned. Copper at 0.5 ppm could definitely cause problems. Levels for aquariums should be below 0.02 ppm.

I wouldn't depend on plants to remove enough copper to bring it down to safe levels. Rather, I would be sure to add an aquarium water conditioner that is advertised to combat metal toxicity. You'll need to add the water conditioner whenever you add new tapwater. As the aquarium gets established, the DOC produced will help keep the copper safely neutralized (via chelation). Furthermore, as time goes on, much of the copper will precipitate out of the water as harmless copper oxides. The problem is mainly when you suddenly expose fish or plants to fresh, undiluted raw tapwater.

Be careful with invertebrates; they are particularly sensitive to heavy metals. For example, you will need to add a water conditioner to the saltwater when hatching brine shrimp eggs. You will never get eggs to hatch in water with 0.5 ppm copper!


----------



## helenf (Mar 24, 2008)

dwalstad said:


> Be careful with invertebrates; they are particularly sensitive to heavy metals. For example, you will need to add a water conditioner to the saltwater when hatching brine shrimp eggs. You will never get eggs to hatch in water with 0.5 ppm copper!


Thanks for the advice. Particularly that last comment! You've just made sense of why I could never get good hatching when I tried to hatch brine shrimp for my fish. I ended up giving up in despair. This was months before I realised there was a copper problem, so I wasn't even thinking about possible toxicity in the water, at the time.

When I get some more time, I'll try again with hatching brine shrimp, with water that has had the copper removed. I wonder if it'll work much better for me than my previous attempts...


----------



## speakerguy (Sep 1, 2007)

The pH is not a problem. There is just no buffering capacity in the water due to low kH. CO2 in the air dissolves into it and forms carbonic acid, lowering the pH. 

The deionized water in the chem labs where I went to university came out of the tap with a pH in the 4.5 to 4.9 range. Adding even the slightest amount of buffer will pop it back up to neutral.

Is this purified water that is pumped through copper pipes?


----------



## helenf (Mar 24, 2008)

I'm not sure what kind of filtering the water gets, though it was my guess that it is filtered somehow to get the PH so low (with low KH, as you point out). It isn't coming out of any special tap or anything, just the main tap in the lab next to my office, But since it's a building full of laboratories, it seems possible to me that the entire water supply is filtered to make the water more useful to those doing experiments. 

Pipes could well be copper. It's a 40-50 year old building and I think copper pipes were commonly used here then, like in my home, actually. But I'm not sure.


----------



## speakerguy (Sep 1, 2007)

The DI water in all of our chem labs (large six-story building, dozens and dozens of labs, largest university in the USA) was de-ionized water and it came straight out of every tap in all of the labs from a central filtration unit. I am almost 100% sure your water gets filtered somehow because of the low kH/gH/pH, but I don't know if that much copper could get into water just because of pipes, etc. 

I think a simple carbon filtration unit would likely take care of your problem. Buy a single stage carbon filter like they would use in an RO filter but get one that has faucet in / 3/4" out connections and hook it up to the tap (that's the way I would go, anyway).


----------



## speakerguy (Sep 1, 2007)

Does anyone know if EDTA is safe in fish tanks to chelate metals?


----------



## dwalstad (Apr 14, 2006)

helenf said:


> Thanks for the advice. Particularly that last comment! You've just made sense of why I could never get good hatching when I tried to hatch brine shrimp for my fish. I ended up giving up in despair. This was months before I realised there was a copper problem, so I wasn't even thinking about possible toxicity in the water, at the time.
> 
> When I get some more time, I'll try again with hatching brine shrimp, with water that has had the copper removed. I wonder if it'll work much better for me than my previous attempts...


I would definitely try again, but this time add a water conditioner to your saltwater. I use Tetra's AquaSafe to chelate the 0.8 ppm zinc in my well water, but there are lots of other water conditioners that will work. Just make sure that they say they'll neutralize heavy metals.

I suspect that these conditioners all contain EDTA, which is cheap, non-toxic and highly effective for chelating heavy metals. [For all those chemists out there, EDTA chelates heavy metals on a 1:1 molar basis. I've used EDTA at 12 micromolar to totally block zinc toxicity towards brine shrimp hatching in my zinc-contaminated water.]

The brine shrimp hatching process is exquisitely sensitive to heavy metals. One excellent scientific study* showed that 0.006 ppm copper would inhibit hatching 50%. Zinc was shown to inhibit hatching 50% at 0.06 ppm.

Finally, using a little old, recycled saltwater has also given me good hatches, as good as those with EDTA or water conditioners. Remember, that old saltwater has lots of natural DOC that will chelate heavy metal chelators and reduce metal toxicity (my book, p. 16).

Finally, carbon filtration removes DOC and organic molecules. It would not be very effective in neutralizing copper toxicity (it doesn't remove the copper ions). In contrast, reverse osmosis, distillation, and some ion-exchange resins could remove the copper.

*MacRae TH and Pandey AS. 1991. Effects of metals on the early life stages of the Brine Shrimp, Artemia: A developmental toxicity assay. Arch. Environ. Contam. Toxicol. 20: 247-252.


----------



## Diana K (Dec 20, 2007)

To raise the KH and GH you could use the Rift lake sorts of products, but because of the copper issue, I would make sure they are not also adding more copper. 

Sodium bicarbonate will add KH. 
Seachem Equilibrium will raise the GH, it has Ca and Mg, it also is high in K (which is a good plant fertilizer) It does not list Cu on the label. If Seachem products are available in Oz you might E-mail them about possible Cu content. 

KH and GH of less than about 3-4 degrees is pretty soft and suggests to me that there might not be enough minerals for the plants. (Except the excess of copper) can you test for other minerals?


----------

