My Tunze magnet cleaner got "weak"

[Travis]

I've noticed something weird with my Tunze algae scraper for the 280. This is the largest sized magnet and my front pane is 1.25" acrylic. I remember when I first started using it, it wouldn't remove coralline. For the first month or 2 after the lights were turned on I had to manually scrape coralline algae off the front pane. This was about a year ago. My whole goal with spending this much on a magnet cleaner was to clean the front often enough that I wouldn't have to manually scrape coralline off. But it seemed that for that first 1-2 months coralline would accumulate no matter how frequently I used the magnet cleaner. Ever since then, the magnet cleaner has been strong enough to remove any coralline on the front pane that is under 1\4" around. I took this for granted and didn't even notice that the magnet went from not being able to remove coralline to removing coralline that is up to 1/4".

Then, last week I used the magnet for a fish trap. I have a bunch of extra pads for the magnet cleaner laying around so I figured I might as well change them out as long as I had the magnet out of the tank. I only changed out the pad that goes on the inside of the tank as this one was starting to look a bit worn down. I didn't change the other pad as it still looked like new. Ever since changing that pad, the magnet cleaner won't remove coralline again. I mean it won't even remove the specs that are so small you can barely see them. Before, it would remove these specs in one swipe. Now I can go over them 50 times and it doesn't do anything. I also notice that the magnet is much easier to move now. I thought this was wierd at first so I let it sit for a few days without touching it so allow the magnets to get to their maximum attraction and it is still the same story. It is easier to pull the magnet away from the front of the tank and it is also easier to slide the magnet along the tank. Before, I had to use both hands on the magnet and my arms would be sore by the time I was done, which only took a couple minutes. Now, I can do the whole thing with one hand and don't even feel anything afterwards.

So what gives? I had never taken the magnet out after I first put it in. Does it really take this long for the magnets go form the strong bond? I would think it would maybe be the new pad but there is undoubtedly less of a bond right now. This really sucks because I HATE scraping coralline off the front pane with a PASSION. First of all, it sucks because the tank is acrylic so you have to scrub and scrub and scrub with the algae scraper to get even the smallest spots. But what makes it even worse is that the tank is in-wall with only access from the back. This makes for an aukward angle for the arms when cleaning the front pane and they get sore really fast. And at this angle it is very hard not to accidentally break sps branches.

 

[rvitko]

The only thing that can weaken a magnet that I know of is heat. I think your coralline is growing thicker and faster and it is not the magnet. At about 140F the magnet will lose all strength. I don't think it is possible for the magnet to lose strength otherwise.

 

[Travis]

The magnet has not been exposed to any excessive heat. It is always in the tank, except for removing it to use it to hold a fish trap against the tank for a few hours and then it went back in the tank.

It just seems strange that the magnet originally could not remove coralline and then was able to after a month or so and continued to be able to for almost a year. Then I switch the inside pad and it is back to not being able to remove coralline again. My coralline is not growing any thicker or faster than it was before. In fact, coralline growth right now is a lot slower than it has been before.

 

[rvitko]

I think it has to be some other variable. I would think algae is like paint. If it has grown over a thin film of a soft algae it would wipe right off. If it grew over a harder substrate it would be bonded like a primer. I could send it to Germany and they could reference it with a gauss meter but I don't have that capability.

 

[Travis]

Let me give it a month or 2. I really don't think it is the algae though. I can tell the magnet is much easier to slide across the front pane than it used to be.

 

[Putawaywet]

Sounds like as the pad either compressed or wore down it allowed the magnets to creep closer together, which in turn applied more force to the cleaning action thus allowing you to get the coralline off the tank.

Replacing the pad returned the distace between the 2 magnets to stock configuration which also reset force of attraction back to where it was once again just beyond the limits of being able to handle the coralline.

BTW Travis, nice tank ya got there.

Brett

 

[Travis]

Thanks Putawaywet, I would tend to think the same but the pad is really not very thick at all. It is about the thickness of 1-2 fingernails. I wonder if the material of the padding itself could be very opposed to magnetic force so that as the material wears down it becomes more porous, hence allowing more magnetic force to pass through.

 

[artful-dodger]

I don't know specifics of this pad since I don't have a Tunze algae cleaner, but I'd bet that the old pad gradually became more abrasive as it aged. Since both new pads (original and the new replacement) seem to have trouble I'd point to that as the variable.

I'll bet money that the magnetic force is exactly what it has always been. (Rather than test the magnet's "strength" by sliding which is really testing friction, you would have to test by separating the two parts. )

 

[Travis]

That is a good point. The pad looked to be very abrasive after it had worn down a bit. I think the new pad helps the magnet to slide more smoothly and that may be why my magnet feels less strong.

I wonder if there is anything I can do to speed up the wearing process on the new pad.... Or maybe something I can do to new pads before switching them out that will get them to a more abrasive state before making the change.

The coralline keeps building on my front pane and I keep putting off scraping it.:lol: I miss the good ol' days when the magnet did it all for me.