Reef Safe Magnets

[vetteguy53081]

I have a few projects I’d like to make for my tank and I need magnets that are safe to use in the tank. I was looking at some cheap epoxy coated ones on Amazon and I was wondering if anyone has used them before. I have also looked at some epoxy coated ones from K&J magnetics, which aren’t too much more expensive.

I dont leave my magnets in water but in the past I coated them with silicone as a barrier to water reaching them

 

[BeanAnimal]

I glanced at the reviews but didn’t notice this one. It makes me wonder if it just depends upon how well each individual magnet was coated, and would the ones from K&J be any different.
Maybe I will buy them and throw them in a cup of saltwater and wait a while to see if they rust.

it does not matter how well they are coated. The magnets outgas as they oxidize due to trapped moisture. They coating swells and micro cracks and allows more moisture….

This even happens with reasonable thick coatings like an acrylic or pvc, etc sandwich poured or solvent welded around them.

 

[brandon429]

It does not happen with plastic dipped k and j magnets, they're perfect for our use. Watch for my updates on year 25

 

[Jasongtr]

Ferrite magnets are safe, its what Maxspect gyres use inside the tank, they are not even coated, its also the same type used by your return pumps which are also not coated

 

[Harold999]

Dont use those, they will rust.

Rust = iron oxide = reef safe. Iron oxide is one the main ingredients of phosphate remover.
Corals grow very well on ship wrecks.

 

[Lbrdsoxfan]

Rust = iron oxide = reef safe. Iron oxide is one the main ingredients of phosphate remover.
Corals grow very well on ship wrecks.

I still dont trust the cheap china made epoxy, so hard pass for me.

 

[BeanAnimal]

Rust = iron oxide = reef safe. Iron oxide is one the main ingredients of phosphate remover.
Corals grow very well on ship wrecks.

"rust" from pure IRON = IRON OXIDE
"rust" from IRON ALLOYS may contain any number of metals and other precipitate compounds...
Most permanent magnets are iron mixed with Nickel, Cobalt and Aluminum
A ferrite magnet is usually strontium and iron...
rare earth magnets are neodymium or samarium-cobalt, etc. alloys that easily corrode and are often coated in nickel, chromium or some other alloy.

 

[Harold999]

"rust" from pure IRON = IRON OXIDE
"rust" from IRON ALLOYS may contain any number of metals and other precipitate compounds...
Most permanent magnets are iron mixed with Nickel, Cobalt and Aluminum
A ferrite magnet is usually strontium and iron...

Correct, but non of the oxidation processes release toxic chemicals in the proces.
For example nickel or aluminium corrosion unlike iron doesn't release anything, what happens is that the metal gets a matte "skin" around itself to prevent any further corrosion.
Pure iron can't do that, it will totally dissolve into iron oxide.

I seriously wouldn't worry at all about a magnet in the tank.

 

[Propane]

A few months back I read a thread on here where the person superglued magnets inside of coin holders to make them water proof. I wonder how that turned out.

 

[BeanAnimal]

Correct, but non of the oxidation processes release toxic chemicals in the proces.
For example nickel or aluminium corrosion unlike iron doesn't release anything, what happens is that the metal gets a matte "skin" around itself to prevent any further corrosion.
Pure iron can't do that, it will totally dissolve into iron oxide.

I seriously wouldn't worry at all about a magnet in the tank.

Again, many of these magnets have alloys that are not reef safe. For example, copper is commonly used in the hard shell of neodymium magnets. The copper will most certainly end up in the water column.

 

[Harold999]

Again, many of these magnets have alloys that are not reef safe. For example, copper is commonly used in the hard shell of neodymium magnets. The copper will most certainly end up in the water column.

Copper on ndm magnets is for decoration purposes. You won't find any copper on normal ndm magnets.

But hey, keep the fear going here if you like.

 

[Mschmidt]

These are what i use for this frag holder.

here they test it.

 

[musicsmaker]

Has anyone used the rubber coated ones instead of the plastic coated? They should slide less on the glass. Just a thought.

Also, what kind of epoxy would/do you use to bond these to some dry rock? I'm looking to make some small "frag racks" out of pieces of leftover rock from my aquascape.

 

[Lbrdsoxfan]

Rubber coated aren't sealed as well. Plastic coated only for longevity.

 

[musicsmaker]

Rubber coated aren't sealed as well. Plastic coated only for longevity.

Thanks for the quick response. Plastic it is!

 

[Lbrdsoxfan]

Thanks for the quick response. Plastic it is!

Its a near and dear one to me, lol. I've tried it all, epoxy coated, diy plastic dip & rubber coated. They all rot. The only ones I've used with long term success (years now) are plastic coated.

 

[WhatCouldGoWrong71]

It does not happen with plastic dipped k and j magnets, they're perfect for our use. Watch for my updates on year 25

@brandon429 - which model number do you use? There are a ton.