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Metals in the aquarium

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I want to use some metal piping in various projects I am doing. Something that is a very good conductor of heat is ideal (copper, aluminum).

After researching quite a bit, all I was able to find was what metals that you definitely should not ever use under any circumstance, ever (unfortunately the best conducting metals are on that list, save gold :().

The only problem is that they never explained which metals were safe, or why the other metals were harmful to fish. I mean, isn't copper safe for human use, why not for fish?

Lots of sites said that it wasn't really the metals that were toxic but rather the oxidization and corrosion that forms on them (that rules out iron and copper I guess), but wouldn't that make metals like aluminum safe? Aluminum forms a very thin layer of oxidization that prevents the actual corrosion of the metal itself, and thusly prevents more corrosion from happening.

I'm honestly confused because of all the different opinions people seem to have.
:help:
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If you do big weekly water changes I doubt that even copper piping in the tank will do any harm, especially if the water pH is around 7 or higher. But, if you use CO2, have a low KH, thus a low pH, and never change the water, both copper and aluminum, as well as lead, will likely become a problem. The pH is involved because acidic water will dissolve metals much faster than neutral or alkaline water.
 

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Pixel Prestidigitator
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If you do big weekly water changes I doubt that even copper piping in the tank will do any harm, especially if the water pH is around 7 or higher. But, if you use CO2, have a low KH, thus a low pH, and never change the water, both copper and aluminum, as well as lead, will likely become a problem. The pH is involved because acidic water will dissolve metals much faster than neutral or alkaline water.
If that were true Hoppy than you couldn't use copper for water at all. The inside is always in water. The problem is two dissimilar metals and salts in the water. No. Not always sodium chloride salt. What you create with dissimilar metals is a battery. That's why metal machines used in water have zinc anodes. They dissolve long before the useful metals. Sacrificial anodes.
 

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Pixel Prestidigitator
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One of my buddies growing up is a water plant manager in NY. I've got a pm in to him asking what they add to drinking water up there.
 

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And here is his response:

Adding caustic raises the PH---has nothing to do with the pipes.. We add a chemical called Zinc Orthophosphate, this is used to coat and protect the pipes from corrosion.

Properties and Certifications

Clear liquid
Totally soluble and freeze/thaw stable
Approximate shelf life > 2 years
Specific Gravity 1.46 ± 0.03
Ratio phosphate/zinc 10:1
pH (heat) < 1.0 ± 0.3
Certified to ANSI/NSF Standard 80



Viscosity < 2 cps at 70° F
Freezing point < -60° F
NSF maximum feed rate 20 mg/L
Total Phosphate 40% ± 0.5%
Sulfate based
Bulk Density 12.2 lbs. per gallon
Evaporation rate: Not applicable
He also went on to say that they do add lye to raise the ph to bring the ph back up after adding the zinc stuff since it's so acidic.
 

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Pixel Prestidigitator
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Oh, I see. The zinc orthophoshate releases the zinc to coat the pipes in acidic or too basic water. Both conditions will corrode the pipes/leach the metals. That's why they aim for 7pH.

Also free phosphate for the plants.
Not sure what they aim for but the water is slightly acidic and very soft. I hate the feeling after a shower like I am still covered with soap. I can't wait to get home to my hard water just to feel clean. They get their water mostly from the DWG and there they add an initial dose of chlorine then when it reaches my buddies plant they add more chlorine to carry it to the end user. They are still chlorine only so pretty good for fish keeping. Bubble it for 24 hours and it's good to go. Supposedly they've got great tasting water. Personally I don't see it anymore. Too much chlorine for me. But then I drink triple filtered RO.
 

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I do not worry about metals I use in my tanks. My thinking runs like this. All of us have different water from our tap but almost all of it has one thing in common. It is pumped with metal pumps, most of it runs in metal pipes and is stored in metal water towers. I t then runs through metal pipes to our house where it either comes in through copper, iron or a few PVC pipes to a faucet that is almost certain to be metal like brass inside.
Do I worry about 5-10 bit of metal in my tank? Not much.

Even if it is corroded and falling apart in 5-10 years, which it isn't, I would still not worry because I do so much water changing to get all the other pollution out that a bit of metal pollution is just not a problem.
I do this game for fun not to make up silly worries.
 

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Copper is realy harmful to invertebrates it will kill your shrimp and snail if you have some i learn the hard way....

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While an excess of copper is definitely harmful to invertebrates, it is still required for them to live (copper is required for hemocyanin).

This is why shrimp food sometimes contains copper.
 

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Despite popular opinion copper isn't harmful in an aquarium filtration system, most people use treated tap which contains trace copper. Not sure I would use Flux and solder but if you can braze with a high silver alloy and purge with an inert gas I don't see why you couldn't use copper. Me personally I would go a step up and get medical gas pipe and fittings which are 2 to 3 times more expensive but are ultra pure and purged.

All that said you can also use stainless steel, a bit pricy but they make compression fittings and the pipe looks quite nice.

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The problem with going to a good deal of trouble to get great plumbing once the water reaches the tank is that it doesn't do anything significant. The water has spent weeks/months in metal and travels lots of miles so I see no great value in changing the last four feet of the journey.
Closing the barn door after the horse is out comes to mind.
 

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The problem with going to a good deal of trouble to get great plumbing once the water reaches the tank is that it doesn't do anything significant. The water has spent weeks/months in metal and travels lots of miles so I see no great value in changing the last four feet of the journey.
Closing the barn door after the horse is out comes to mind.
I enjoy a well crafted plumbing system in aquariums but that's just my opinion, a huge draw to the hobby is equipment and diy. I have a few fish that definitely keep me interested but the majority of the fun is in setup design and creation, and who could forget the routine maintenance and feeding haha

That said if you can shell out the cash a beautifully brazed copper plumbing system is nice. If you use valves make sure they're ultra pure and meant for medical use.

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