Tunze Osmolator Nano 3152 ATO Rusting

[rmclaughlin87]

I purchased a Tunze Osmolator Nano 3152 auto top off from Marine Depot less than a year ago. Over the last month or so, some of my coral started to look unhealthy. Most of these have been in my system for years, so I wasn't sure what was going on. I ran all my normal tests - ammonia, nitrite, nitrate, ph, mag, calcium, alkalinity, etc., and everything was still testing normal. I decided to do a thorough cleaning of everything, so I tore out all the equipment and did a large water change. While unhooking everything though, I found what looked like a brown stain down the back side of the sump area in my biocube. Upon looking at it further, I found that the magnet on the ATO float sensor was rusting. All in all, I lost a couple pieces of LPS and two frags of zoas. Not the end of the world, but I would have expected better quality from a reputable manufacturer like Tunze.

 

[misael888]

Wow!! Sorry about your losses, But glad you found the problem. Rust will serntly affect your water chemistry. I was considering buying the same ATO for small system I'm setting up, but now I may need to find a different option thanks to your post!!

 

[rmclaughlin87]

No problem. I am by no means here to bash Tunze. They have one of the best reputations in the aquatics industry. I'm hopeful that my issue was a fluke...just a small oversight in quality control. In regards to the functionality of the system, it worked great - always kept my water level consistent. If they address the magnet issue, I would have no problem recommending this product.

 

[jgalen0025]

No not at all isolated. I have had two of these problems, one with a 9004 skimmer magnet and the nano osmo magnet. They both were leaching rust but some dont. I am not sure what causes it but very disappointing to say the least!

 

[tjgr34]

I'm setting up a system with a 9004 now- do you think putting epoxy over the magnets would fix the problem?

 

[edinphilly]

I thought I read somewhere that they come with in tank magnets that are protected and won't rust, as well as outside magnets not meant to be in the tank which aren't protected.

 

[rmclaughlin87]

That's too bad to hear it's not an isolated case. It seems like something like this should have been resolved a long time ago.

@tjgr - epoxying the magnets should work. I feel like this should have been done by Tunze if it was a known problem.
edinphilly - maybe they have addressed this issue on the newest ones. The magnets aren't protected on either side on mine. They came preattached to the float switch and outside mount.

 

[dangerbird123]

Got one a couple years ago which rusted due to the magnet being exposed to the water. Got one last month and it looks like they have taken care of the problem - the magnets are all sealed up so shouldn't be a problem

 

[mcarroll]

You should post (also) in the Tunze forum. (Doh.)Both for information as well as for possible warranty. (Or call or email them. They're very friendly and helpful and they generally have significant warranties on their equipment!)

I can add that the smaller magnets that appear to have a glossy coating are neodymium. The glossy coating is epoxy, which is tough but isn't perfectly impenetrable. (IIRC this is mentioned in the manual...been a while since I've read one tho) Neodymium will corrode in saltwater if the coating is compromised.

Newer units have "inside" magnets(Doh.) that are quite a bit larger and made from ferrous metal. It looks a bit rusty to start, but WILL NOT corrode in saltwater and has no coating.

It's an interesting problem to hear about....never hear of this happening outside of theoretically.

Good luck on the rebound!

-Matt

 

[rmclaughlin87]

I'm glad to hear that they made this improvement on the new models. I did email Tunze too, so we'll see what they say. Thanks again for the info!

 

[mcarroll]

Or I could be slightly wrong.

Ya know, after looking mine are installed reversed from how I described. The larger, ferrous magnets are on the outside. The neodymium is on the inside of the tank. And now I can't find the post/email that explained the difference with the newer magnets....must've been a phone conversation with Roger@Tunze.

-Matt

 

[mcarroll]

Here's some info Tunze published elsewhere (abbreviations and emphasis mine):

These are the new magnets, they are Ferrite, the same material most impellers are made from and will not corrode. [...] The only way these will get any corrosion is if iron particles stick to them, the attracted iron will corrode but the ferrite itself will not.

Metal particles are surprisingly common in most/all of the crushed coral/sand (I know people who drag magnets through their new sand before it goes into the tank)....possibly from other sources as well. Something to consider.

(Any chance of posting a picture?)

-Matt

 

[rvitko]

Before anyone gets carried away I want to explain some things about how these magnets are built and what choices exist in magnet holder construction.

I will start with my reply the Ryan by email which explains why we do not believe coral loss can be related to the magnet holders, their is nothing remotely toxic used in the construction of the ferrite magnet holders-

"I don't believe any connection can exist between the magnet and the loss of corals. The magnet is ferrite, this is the same inert ceramic magnet impellers are made from. Under this is an iron plate, this iron plate is coated in polyurethane for waterproofing. It is not plated in any toxic metal, no zinc, nickel, etc. Iron is generally regarded as reef safe, at worse it can feed some algal growths and their is some debate about it being an irritant to Tridacnid clams, but based on the fact that many corals flourish on rusting ship hulls and oil rigs and that many aquarists add rust every day in the form of GFO (granular ferric oxide or pelletized "rust" as phosphate remover), would lend strong support to this material being non toxic. While the magnets were recently changed, this was to reduce size and cost, they are thinner and use a very small neodymium magnet, neodymium is quite toxic and that is why it must be coated, but in the case of neodymium magnets, if the coating were to fail, it can poison corals with longer term exposure. Ferrite cannot be coated as it is quite weak magnetically and it does not need to be coated as it is inert, the iron plate serves to bridge the fields so the magnets act as a unit and not as two magnets. I would be happy to replace your magnet under warranty if you can provide photos and a copy of the invoice, however, I would vigorously refute that the magnet holder could possibly poison the corals or result in losses, about the only biological impact that would be plausible would be an increase in algal growths. Nothing in the magnet holders differs from elements and materials that a reef aquarium is routinely exposed to, even if the polyurethane coating fails."

I want to add that basically we have these two choices in magnet construction, ferrite and neodymium (rare earth). If you have followed this for some years you know that we switched to ferrite in 2010, in 2008 the Chinese nationalized production of Neodymium, they are the source of 98% of this material, they limited production, raised the price 600% and then added a 50% discount if you finished your product in China. At that pricing and not being willing to move production to China, the magnet holders would have cost to build what they sold for. Ferrite is the everyday refrigerator magnet or impeller magnet, it is a manmade ceramic that holds a magnetic charge. It is weaker, but it is available from hundreds of sources and is also inert. We switched so we could keep pricing flat. While their are other types of magnets, samarium, alnico, etc, these exotic types of magnets require special handling, have limited applications and in the case of alnico, very long lengths, to be effective and are not suitable. The honest truth is that the non coated magnet holder is as safe as it gets, neodymium does seem to have a strong level of toxicity and is often nickel plated as it is very reactive, neodymium comes in various grades and come also as a rubberized powder (flexible magnets), they all have to be coated somehow to be submerged and just as it can in the ferrite magnet construction it can fail and with worse consequences, but because they are so strong, they can be liberally coated.

To be fair, we use magnet holders because suction cups just suck, they will always fail someday no matter how you build them and clamps are tricky and difficult to configure for all possible tank installs. The magnet is the best we have and I would argue we build them better than anyone else, sure, we may have a defective unit occasionally, but I would strongly refute that they are poorly engineered or lack thought into safety. In this case, I cannot plausibly see a connection between the magnet and any loss of corals and I will continue to say that the most common cause of so called magnet rusting is that the magnet picked up something which rusted, I see it every day, that little cloud of a new GFO charge sticks to the magnet and stains it and people blame the magnet for rusting, without even acknowledging they just added 500 gms of rust on purpose. And, we are not blameless either, I have seen the magnets have iron particles on them brand new out of the box, the Ferrite comes as a log and it must be sawed and the sawing produces filing which stick to the magnets. However, keep it in perspective, it is only iron, their is no strange toxin used, no mysterious formula and I think if you look at the whole picture of the consequences when a suction cup fails and an item falls or worse a pump rockets around smashing up your tank, you will see that for whatever possible flosses, we have made the best possible solution and implemented it the best we can. The main point of the new magnet holder we just started implementing was simply that the 3M bumpons are quite expensive, the new system uses a silicon ring we make in house and it looks nicer and is thinner and more compact. Neodymium has come down in price due to so many companies much bigger than us like GM and GE also switching to Ferrite for motors and other products and it takes about a watch battery size piece of Neodymium to equal the strength of one of the Ferrite pieces we use which are quite large.

 

[mcarroll]

Roger, you and Tunze give the best, most complete support answers in the biz. It's like breathing fresh air! Thanks as always!

(I am also still curious to see a pic of the magnet in question.)

 

[rmclaughlin87]

Roger, thank you for the thorough explanation. I trust your response as you're much more of an expert than I. I will post a pic for reference. I do not run GFO, and the float switch magnet has been in the same place since I received it. As you said, maybe it picked up some particles in production. From my POV, its a nerve wracking sight though when you see rust in the tank.

 

[mcarroll]

[...]From my POV, its a nerve wracking sight though when you see rust in the tank.[...]

Completely understandable! When you're troubleshooting a "coral outage", or just about any problem, sometimes the first piece of "evidence" you come across gets all the blame....whether it's involved or not (could be pure coincidence), and whether it has co-conspirators or not (still-unknown factors). Regardless of the magnets, I'd surely keep looking for more clues as to what's ailing your coral. (Which, in addition to your other options, you're welcome to PM me on if you like.)

Good luck!

-Matt

P.S. Pardon the rhetoric...I may have spent too many years as a WAN troubleshooter.

 

[dangerbird123]

Interesting read. Checked my original with the rust which I've continued to use because I never had any ill effects - rust had not worsened after more than a year so I'm a believer that in my case it's just iron filings or something stuck to the magnet.

 

[rvitko]

Ryan,

It is pretty clear from the photo that this is due to a defect and the iron in the magnet is rusting, the staining shown would most likely be from that source as it is around the magnets at the polyurethane, please email me your address.

 

[rmclaughlin87]

Thank you Roger! I really appreciate all of your help on this. Amazing customer support!

 

[Hogan]

I have two of these and basically have the same story as this. Looks the same, same problems, no gfo on either and one is a bare bottom tank. How did you fix it?