Tunze Pump 6025 Magnet Rusting

[Da Maui life]

I bought two 6025 pumps February 28 2014 and took them off for cleaning and found rust on the magnet, and back of my acrylic tank ETCHED in, BTW.

What’s up with your magnets rusting?

 

[rvitko]

The magnets themselves are ceramic, the same ceramic that almost all impeller magnets are made from and they cannot rust. One of two things is at play here. Either something iron that could rust was attracted to the magnets, this could be some iron filings, steel wool, a staple etc, anything it may have picked up at some point. It is most commonly bits of iron based phosphate remover which it has picked up. The other possibility which is far less common is that the ferrite magnets sit on an iron plate, this plate is coated by polyurethane, it can have a breach where saltwater gets to the plate and the plate rusts, but usually then you can see a single pin hole source of the rust.

 

[Da Maui life]

Roger,

Thanks for responding I was aware of the magnets made of ceramic, it's very possible some sort of debris iron was on the magnet. The rust follows all the way down into bottom of the channel of the base plate. If the magnet sits on an iron plate and the rust is from a pin hole on the coated polyurethane iron plate how would you see a pin hole down in the channel? I suspect if the rust is all the way down, then this could be the problem. I have cleaned it out with a tooth pick and will check in a week.

 

[rvitko]

One possibility would be to soak the magnet in something like CLR that removes rust stains, after a thorough rinsing it should be fine, I have used CLR to clean pumps before without issue, I believe it is mostly phosphoric acid. Once it is clean, you should be able to see if their is a point where the stain was very strong, a small bubble in the black resin around the magnet, then that would likely be a hole and it is actual rust. Of course, if it came back in the same place that would also point to rusting of the plate.

 

[Da Maui life]

The magnets themselves are ceramic, the same ceramic that almost all impeller magnets are made from and they cannot rust. One of two things is at play here. Either something iron that could rust was attracted to the magnets, this could be some iron filings, steel wool, a staple etc, anything it may have picked up at some point. It is most commonly bits of iron based phosphate remover which it has picked up. The other possibility which is far less common is that the ferrite magnets sit on an iron plate, this plate is coated by polyurethane, it can have a breach where saltwater gets to the plate and the plate rusts, but usually then you can see a single pin hole source of the rust.

So I have cleaned this out twice after my last post and the rust keeps coming back, I don't run GFO BTW and I'm not impressed with the quality or the holding power of the magnets.

 

[rvitko]

They are rated to hold on up to 3/8" glass, if you need more holding power it requires upgrading the magnet set with either 6025.501 for 1/2" or 6025.500 for 3/4". If you email me the invoice I will send a replacement magnet.

Tunze at sbcglobal dot net

 

[Da Maui life]

Thanks for the reply and up-grade info, I do appreciate it. My acrylic tank is about ⅜” ‘metric equivalent’ but it’s barely hanging in there. contact info sent.