Why are magnets bad for reef chemistry ?

Benjamin28

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Why are magnets bad for the reef tank?

I have read many threads where individuals blame magnets for all kinds of misery. I am getting ready to make some magnetic accessories for my tank but I want to be prepared for my consequences if I fail to adequately protect them from poisoning my tank.

I am looking for real explanation and not assumptions please. Also what chemical would I or can I test for to measure a magnets affect on the tank.

Thank you
 

Harold999

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Because they are not always sealed properly and if saltwater gets inside they will rust.
Even then, rust (iron oxide) isn't toxic. GFO contains a form of iron oxide.
Corals love to grow on shipwrecks. :)
 
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Jedi1199

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Why are magnets bad for the reef tank?

I have read many threads where individuals blame magnets for all kinds of misery. I am getting ready to make some magnetic accessories for my tank but I want to be prepared for my consequences if I fail to adequately protect them from poisoning my tank.

I am looking for real explanation and not assumptions please. Also what chemical would I or can I test for to measure a magnets affect on the tank.

Thank you

I use magnets exclusively for attaching items to the tank (frag racks, heater, wavemakers, ect).

If there is a downside to this, I am unaware of it.
 
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hart24601

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Impeller magnets are, for the most part, not coated. I expect Randy will give the definitive answer but I suspect the issue is impurities (or added on purpose) in magnets that are not intended for reef or aquarium use. I don’t know enough on magnet manufacturing to know what heavy metals would be added.
 
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Jedi1199

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Impeller magnets are, for the most part, not coated. I expect Randy will give the definitive answer but I suspect the issue is impurities (or added on purpose) in magnets that are not intended for reef or aquarium use. I don’t know enough on magnet manufacturing to know what heavy metals would be added.

This makes no sense to me. Most (if not all) impellers are magnet driven. If there is an issue, I believe it stems from the post the magnet is attached to, not the magnet itself.

It IS possible that some manufacturers use iron based material for their magnets, but the majority of what you find today are "rare earth" magnets.

Again, I use magnets for everything in my tank and have never observed any issues related to the magnets.
 
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hart24601

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The reason I brought up impellers is because I agree they are not an issue and are not coated although some are. However these magnets are expected to be in constant contact with sw.

I do not know if there is a chemistry difference between magnet grades(if that exists) or what is used in impellers vs other magnets, if I was to buy a magnet off eBay and put it in my tank uncoated would it be fine? I don’t know - just saying it’s possible and I look forward to someone with more knowledge on magnets and their exact composition.

perhaps the dozens of people who claim issues are wrong and there is no way any magnet could harm a reef tank or perhaps you have been simply been lucky. I was only offering one idea that the composition of magnets might vary and their reaction to sw therefore would also vary.
 
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encrustingacro

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Even then, rust (iron oxide) isn't toxic. GFO contains a form of iron oxide.
Corals love to grow on shipwrecks. :)
There are many different types of iron oxides, which depends on what type of iron ion is in the compound. Maybe some iron oxides are toxic while others or not, or maybe it depends on if the iron oxide dissociates into the water? Also, for the shipwrecks part, the iron oxide probably dissociates into such a large volume of water that it doesn't really matter all that much.
 
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Benjamin28

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I did some research and seems that some of the strongest magnets are coated with multiple types of metals with copper being one of them which is a big no no in a reef tank!
Can you attach a link to where I can read up more on this? Obviously, I don’t want magnets to rust and dissolve in my tank and make the water turn orange. However, the pump magnets being safe and others not has me question if I can find magnets that I don’t even have to worry about if my plastic and acrylic glue bond breaks.

I would like to use rare earth magnets made of neodymium and Cobalt and the only negative I can see is excess cobalt could cause a result in a diatom outbreak but there is little research on the specifics of trace elements.
I am starting to question when people say they found a rusty magnet or pipe clamp and blame that on a tank crash if that wasn’t the problem.
 
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Benjamin28

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Thank you everyone. You’ve given me the confidence I needed to just do it. If I have massive problems in the future I will just get an ICP test do a massive water change and run couprsourb.

the only magnets I can find that are actually toxic to coral are copper magnets so I feel safe unless someone blows my mind before next week.
Take care you all.
 
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ZombieEngineer

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Can you attach a link to where I can read up more on this? Obviously, I don’t want magnets to rust and dissolve in my tank and make the water turn orange. However, the pump magnets being safe and others not has me question if I can find magnets that I don’t even have to worry about if my plastic and acrylic glue bond breaks.

I would like to use rare earth magnets made of neodymium and Cobalt and the only negative I can see is excess cobalt could cause a result in a diatom outbreak but there is little research on the specifics of trace elements.
I am starting to question when people say they found a rusty magnet or pipe clamp and blame that on a tank crash if that wasn’t the problem.
Rare earth or neodymium magnets will kill every coral and invert in your tank pretty quickly. Even if these are epoxy coated, if the coating cracks that tiny hole can sometimes leach fast enough to kill coral. The only safe magnets are ceramic or very well coated stronger magnets.
 
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Erin1971Texas

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Thank you everyone. You’ve given me the confidence I needed to just do it. If I have massive problems in the future I will just get an ICP test do a massive water change and run couprsourb.

the only magnets I can find that are actually toxic to coral are copper magnets so I feel safe unless someone blows my mind before next week.
Take care you all.
Reach out to some of the folks on the 3D printing forum. Many make items that have magnets attached; they can probably advise you on what to buy/avoid.
 
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Derrick0580

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They say that they coat in nickel and copper. There are plenty of magnet sellers that sell plastic or epoxy coated magnets and there are also videos on youtube showing you how to mix up epoxy and make your own coated magnets.
 
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Benjamin28

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Rare earth or neodymium magnets will kill every coral and invert in your tank pretty quickly. Even if these are epoxy coated, if the coating cracks that tiny hole can sometimes leach fast enough to kill coral. The only safe magnets are ceramic or very well coated stronger magnets.
What about samarium cobalt magnets

I hate to be stubborn but I am looking for a reference book, journal or chart that shows or explains the toxic effects of these elements. If it’s a long explanation I don’t need it posted, I just want to know where to read to get the full in-depth answer.
 
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Benjamin28

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They say that they coat in nickel and copper. There are plenty of magnet sellers that sell plastic or epoxy coated magnets and there are also videos on youtube showing you how to mix up epoxy and make your own coated magnets.
Thanks for that link, the manufacture explaining what and why they coat their magnets with is very helpful and we do have lots of resources on copper in the aquarium so that will help my decision making process.
 
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HBtank

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I am fairly certain a magnet on a “frag mount” crashed my tank. Never could figure out what did it, but I am in the process of restarting my tank and while going through old stuff found that dang plug with a colony on it. Was a heartbreaking moment, such a cheap and small piece in my tank. The corrosion was obvious behind the epoxy seal, I did not notice it then, but when you are cutting out huge colonies of dead coral from a crashed tank you kind of have given up at that point.

Regardless, only use magnets from reliable sources that seal them properly or use safe materials. This one was from some random source.
 
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brandon429

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I'm sure liking my K&J plastic coated magnets. Fifteen years submersion and no corrosion? Rock on kj

 
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Randy Holmes-Farley

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Why are magnets bad for the reef tank?

I have read many threads where individuals blame magnets for all kinds of misery. I am getting ready to make some magnetic accessories for my tank but I want to be prepared for my consequences if I fail to adequately protect them from poisoning my tank.

I am looking for real explanation and not assumptions please. Also what chemical would I or can I test for to measure a magnets affect on the tank.

Thank you

There are lots of different metals that magnets can be made from. And many of those can potentially corrode and be toxic.

It will be much easier to buy or make plastic coated magnets than to try to figure out which uncoated magnets are ok.
 
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