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The Ultimate Guide To Reef Safe Magnets For Aquariums!

As more and more people decide to start keeping a reef tank or general saltwater aquarium, we have noticed a spike in the number of people reaching out about reef safe magnets recently.

We can definitely see why so many people are reaching out about high-quality magnets for their reef tank too as a large number of “aquarium safe magnets” will end up having issues in the salt water of a reef tank.

Depending on your exact situation, you may actually better off just going with some reef safe putty rather than an actual magnet set.

Reef safe putty allows you to securely hold coral and other items in your tank in place with ease while not having to deal with the potential problems of adding magnets to your reef tank.

Another use case for reef safe putty that is becoming increasingly popular is to coat a magnet in the reef safe putty, let the putty set and then add the magnet to your reef tank.

Although this can work very well and is a very popular option, this does still present a minimal risk to your tank but it is generally much safer than just using magnets without any protection.

Which Magnets Are Reef Safe?

The general consensus is that the majority of ceramic magnets are reef safe where as neodymium magnets are not reef safe unless they have been completely encapsulated in something like reef safe putty or epoxy.

Even then though, some ceramic magnets can cause problems in a reef tank due to any coatings or mounts that the magnet may come with.

For example, a large number of ceramic magnets that you can purchase in general hardware stores have iron oxide and strontium carbonate in them and will cause issues with a reef tank.

As it is very difficult to find magnets that have been specifically designed for use as aquarium safe magnets, we would always recommend that you coat them in a reef safe putty if possible.

This will reduce any potential risk of the magnets contaminating your reef tank and causing issues with water quality.

Notice that we used the term “reduce” rather than remove any potential risk as this method does still have a small risk of the putty ripping and allowing the tanks water to come into direct contact with the magnet.

Are Ceramic Magnets Safe For Reef Aquariums?

All ceramic magnets are not created equally and although some are reef safe, many do have iron oxide and strontium carbonate used in their construction and will present a risk to your reef tank.

It can be difficult to get definitive answers on if a ceramic magnet has had iron oxide and strontium carbonate used in its construction or not due to most ceramic magnets being designed for use where iron oxide and strontium carbonate will not cause a problem.

We know that this is going to take time to “quarantine” the magnets before adding them to your reef tank but this method is worth doing as it can prevent you from accidentally adding non-reef safe magnets to your tank.

If you are set on using some ceramic magnets in your reef aquarium then add them to a glass containing some of the water from your reef tank and leave them for two weeks.

Although the two week waiting period may seem like a long time, it can take as long as a week for the iron oxide in some ceramic magnets to start to show the signs of rust so giving it two weeks ensures it has plenty of time to develop.

You can then use a saltwater test kit on the water in the cup that has had the magnets in it to check for any abnormalities before deciding if you want to add the magnets to your reef aquarium or not.

Are Neodymium Magnets Safe For Reef Aquariums?

Neodymium magnets rust very quickly and will end up causing problems in your reef aquarium quickly.

You are able to coat a neodymium magnet in a reef safe epoxy prior to adding it to your reef tank but if the epoxy or putty rip then it is highly likely that you will still have issues.

We have seen some neodymium magnets marketed as being “reef safe” recently due to having a plastic case wrapped around the magnet.

Judging from the reports that we have seen, the plastic has not been attached to the magnet very well and they quickly started to cause issues. This is why we recommend that you avoid neodymium magnets in your aquarium as the risk tends to outweigh the reward.

If you have no other option and you have to use neodymium magnets in your reef tank then coating them in reef safe putty is probably your best option but as we touched on, if this rips, you will have problems.

Some people also use No products found. to coat their neodymium magnets prior to adding them to their tanks too but this tends to take too long to be a practical solution with putty usually being much quicker.

Do Magnets Rust In Saltwater Aquariums?

Neodymium magnets will quickly start to rust in saltwater and any ceramic magnets that have had iron oxide and strontium carbonate used in their production will also start to rust within two weeks of coming into contact with water.

Ceramic magnets that have not been made with iron oxide and strontium carbonate are generally considered to be reef safe and should not cause any problems though.

As we covered earlier in the article though, it can be difficult to find ceramic magnets that you know have definitely not had iron oxide and strontium carbonate used in their production though.

For the most part, magnets are not made for use in reef tanks or even general aquariums so the brands may not specify the use of iron oxide or strontium carbonate in their production.

Just because you see one ceramic magnet say it has used iron oxide and strontium carbonate and another not specifically say that they have does not mean that the one that does not state iron oxide and strontium carbonate were used have not used them.

This is why we recommend that you use the quarantine procedure for any ceramic magnets that we described earlier in the article as it is the best way to find out if your ceramic magnets will rust or not.


That brings our article going over reef safe magnets to an end. We hope that you have found our article helpful and that we have been able to help you better understand the risks of using magnets in your reef tank. As we have mentioned various times throughout the article, even a magnet that is coated in a suitable putty, glue, or epoxy can still end up having problems so we usually recommend you do everything you can to avoid using magnets in your aquarium if possible.