Beware of Vinegar - The Pump Killer

[AltitudeAquarium]

I have posted bits and piece of my vinegar story over the past three years, and I thought it would be beneficial if one post contained all that I've learn. You'll be surprised! This story will contain three parts; my history with vinegar, the cause and simplified chemistry what's happening; and the solution to cleaning your pumps without fear of swelling magnets.


MY STORY

I've been using MP's for many years, and as a good boy, cleaned the wetsides in vinegar (aka, acetic acid) to make them look good and function correctly. I had a very simple way of doing this by immersing the entire wetside in straight vinegar over night and then rinsing and putting back into service.

If anyone is interested, this small plastic container that perfectly fits an MP40 wetside is a one pint talenti ice cream (gelato) container....an overpriced ice cream my wife enjoys....too many times!

About three and a half years ago I found one of my MP40 wetsides slowly spinning. To be crystal clear, the entire wetside...cage and all, was spinning. When I pulled it out I found the magnet had swelled and was binding to the body of the powerhead, causing the entire thing to spin.

I wasn't a happy camper, but over the next couple months, two more were found with swollen magnets (plastic case either swollen and/or cracked), and now also not functioning.

Now this isn't just an MP thing. In retrospect, I had four Koralia Evolution powerheads before switching over to MP's. All four were dead in the water within a year of purchasing new. Two with obvious swollen magnetic portions of the impeller shaft, and two that I couldn't even get the impellers out of the body of the powerhead because they were swollen and stuck within the body. Note that these powerheads were also regularly cleaned in vinegar.

So I have a confession...."Bless me Father for I have sinned"....my wife didn't know what I paid for all the MP's I have...and now I need to go out and drop another $225 for three wetsides. I wasn't happy!!! Note, if I die, my wife will be selling MP40's for about $20 - $25, half of what I supposedly paid.

To finish this story, I later had three MP10's do the same thing. My wife will be selling these for $15 - $20 a piece. Now I know, with six MP's with new wetsides, you're all waiting for me to die!


WHY IMPLICATE VINEGAR

So I was puzzled why my overpriced MP's crapped out, and about six months after loosing my first MP, I came across a post by @Randy Holmes-Farley in which he posted:

"I think the effect on plastic may be worse with vinegar than muriatic acid but it may depend on the plastic.

Vinegar can be in the form of acetic acid and that neutral molecule can enter plastic. Diluted muriatic acid won't have any neutral acidic molecules in it to enter plastic, so just exposes the outermost leading edge of plastic. So while the muriatic acid after dilution is a much stronger acid, i would not assume it is worse on plastics."


This made perfect sense! To clarify, charged molecules won't penetrate plastic, but neutral small molecules will. I will repeat that saying it differently....ionic molecules will react at the surface while small neutral molecules will potentially penetrate that material.

If we look at acids in aqueous solution, they dissociate into ions, which is commonly shown as:

HA(aq) + H2O(l) ⇌ H3O+(aq) + A−(aq)

where HA is the acid. Note that the left side is "neutral" while the right side of the reaction contains "charged" molecules (ions). Specifically, for acetic acid (vinegar), this dissocation looks like this:

CH3COOH + H20 ⇌ H3O+ + CH3COO-

Now here's the kicker....some acids dissociate easily and readily while others dissociate very poorly. In the case of acetic acid, it dissociates very poorly, with the majority still in the neutral CH3COOH configuration. To repeat what I said above, charged ions do not penetrate, while small neutral molecules can.

So what is happening when you clean your parts in vinegar, is that it being neutral, has the abililty to penetrate the plastic and, if within the plastic is metal, cause it to oxidize (rust), and swell. Now this doesn't happen over night, or by one cleaning, but happens over time....months, maybe years, but it will happen. In addition, the type of plastic could impact how quickly (or slowly) the acid penetrates.

Don't get me wrong, vinegar is still great for cleaning tanks and pure plastic parts, but I'd avoid it with metal parts encased in plastic (impellers and pumps.) If the cages alone need to be cleaned of coraline, I'd still consider cages only to be soaked in vinegar. But plastic encased magnets...NO, NO, NO!


IF I CAN'T USE VINEGAR, WHAT AM I TO DO

So what can you use to clean your powerheads and pumps that won't potentially cause the magnets to rust and swell and ruin your pumps? We need to find acids that dissociate completely and/or are too large to penetrate the plastic.

Well there just happens to be two readily available acids available that are reasonably price, and in my opinion, with one, clean better (faster) than vinegar. These two acids are Muriatic Acid and Citric Acid.

Muriatic acid (dilute hydrochloric acid) is available at HD and pool stores (and I'm sure other places as well.) One note with muriatic acid, it is hydrochloric acid and needs to be handled with care. It will burn you, cause for holes in your cloths, and is dangerous. So wear rubber gloves, eye protection and be careful.

For cleaning tank parts, I'd recommend dilution 1 to 10. Even at this dilution, it will clean pumps and whatever, much faster than vinegar. You'll actually see the calcification fizz off the equipment.

The other acid that is pump safe is citric acid. You can find five pounds on ebay for a reasonable amount of money....a life time supply. Here you want to dilute about 1 cup to a gallon of water. Throw your pumps into this solution and allow to sit over night and you should find a cleaned pump


CONCLUSION

Vinegar, being a neutral acid, will penetrate plastics. If metal is encased in this plastic, it will find it's way and cause that metal to rust and swell. To avoid this, use other acids, such as muriatic acid or citratic acid to clean your pumps...and have them last forever!

I have Koralia nano pumps. I read someone else's post that after cleaning they lubricate with vaseline. I did know that was safe for my aquarium. So what should I use after cleaning with acid, rinsing with water to lubricate the shaft?

 

[redfishbluefish]

I have Koralia nano pumps. I read someone else's post that after cleaning they lubricate with vaseline. I did know that was safe for my aquarium. So what should I use after cleaning with acid, rinsing with water to lubricate the shaft?

First off, I'd never use a petroleum based lubricant on anything fish related, and certainly never, ever on anything rubber. If you want that clean new look, I'd consider a very light coat....put it on and wipe it off....of a non petroleum based lubricant, such as non petroleum plumber's grease, or what I use on rubber parts, Leslie's Pool Lube...

Note this is an old tube....maybe 20 years....they've since changed the graphics.

 

[SeaDweller]

duly noted.

 

[Sisterlimonpot]

Lets look at this from a mechanical perspective. Also let me preface but saying I didn't dissect my MP40 wetside. However there are certain assumptions that can be made.
1. The propshaft has to get sealed between the magnet section and the prop side.
2. Those seals would wear do to the shaft spinning non-stop over a year or two.
3. Depending on the material of those seals cleaners and acids can do more harm to them. Any soaking would degrade these seals further.


Before I installed my new MP40s in my tank I looked at the wetside of the pump. The cage is easily removed from the base. The cage part would be an easy item to clean with whatever a person wanted to use.

However when you remove the cage from the wetside there is an O-ring between the cage and base. Also the prop rides on a Stainless steel shaft. I'm pretty certain over a short time the acid would eat these parts. I didn't take them apart any further. But I am certain Muriatic acid is a no go on these due to the metal shaft and O-ring.

I for one would clean the cage separate from the base. The base section I would take greater care with because of shaft seals. I would also inspect it for signs of wear.

I also tend to thing of the wetside as a time replacement item. When something runs all the time 24-7 it's going to wear out. Unfortunatly the seals will fail before anything else and then cause the magnet and everything else to fail afterwards.

When it comes to the MP's I was more familiar with the construction of the 1st generation ones like in the pictures redfish posted. However I have an extra set of the 'latest' generation wetsides (makes things easier for maintenance, I can simply swap them out when it's time for a cleaning.... no down time!!). That gives me great opportunity to pull them apart to focus on construction.

Also, attached to my tool box in the garage, I have a couple of the old MP40 wetsides (2 on the right). No idea why I kept them, but they will come in handy today.

Looking at construction of all of them, it's apparent that even the few that I have went through a series of iterations. First thing I noticed on all of them is the magnets are manufactured separately from the other components. This makes sense for a couple reasons, primarily it ensures the magnet is completely encased in plastic. Below is the old version, the new ones are glued together.

Only known to Ecotech engineers, the thickness of the magnet casing and if it has been changed over the course of iteration (I would venture to guess that it has) as well as plastic composition.

If you notice that the older wetsides didn't have any metal parts, except the obvious sealed magnet. They also incorporated a small ceramic or porcelain piece that contacted a harder plastic composite to prevent premature wear on the rotating components. There were a lot of flaws in this design. Because the shaft didn't have an upper support the magnet and propeller assembly relied heavily on everything being balanced, but if you were like me, you took them completely apart for cleaning and it would never balance correctly afterwards. Note the differences from the properller shaft assembly of the old versions (clearly they were making corrections as problems arise).

All this to say that if you've been a long time MP customer, you'd remember that you could simply purchase the magnet for $50 when it swelled and be done with it, but that exacerbated the balancing issues. Now-a-days if you have a swelled magnet the entire wetside is scrapped for a new one.

The new ones are all glued together allowing you to only break it down into 3 sub-assemblies. Also the upper shaft is supported and requires a stainless steel inner shaft and a ceramic or porcelain outer shaft. I believe that stainless steel is resistant to oxidation from acid to a point, which is a good reason to stay away from muriatic acid that isn't sufficiently diluted.

You can also see that the bottom side has the harden plastic composite that rides on the white ceramic or porcelain washer on the bottom.

And that the entire rotating assemby is glued together making it impossible to remve the magnet for replacement.

You can also see that that hard plastic composite runs along the entire inside of the prop shaft. Making the wetside last a lot longer than you would expect. I don't think Ecotech calls this a wearable component....

As for the rubber o-ring, I removed one once, and it stretched making it impossible to put back in. Not sure if it was due to me pulling it out or from the mild acid baths, but I wouldn't touch those seals.

To tie it all in, this was my last rusted magnet, it's apparent that this happened due to personal neglect.

In my fish room I have a washer machine solely for my filter socks. It doubles as a horizontal work surface. Upon cleaning this one and setting it aside, it slammed down onto the metal washer machine. Neodymium magnets although powerful, they are brittle. That cracked the magnet and appears the casing as well, it went back into the tank and upon next scheduled cleaning it was discovered. Even 3 months outside of the 1 year warranty, and clearly no fault of their manufacturing they replaced it.

There is very little doubt in my mind that this has been an issue and just because we haven't received any formal reports from Ecotech that the problems has/is being addressed.

These days, I wonder if most (or all) the reports of magnets aren't due to our handling of them. I personally reserve my opinion until I hear that it's impossible to combat against the neutral ions from penetrating any type of plastic composite. If you prove to me that it can, than it's safe to assume that the R&D teams have already corrected the issue.

 

[redfishbluefish]

@Sisterlimonpot , very nice summary of the history of the MP40's. FYI, the old magnet plastic coverings were in fact glued/welded together. You can see the seam in one of my failures in the first post. I also did a mini Reader's Digest version of the differences HERE. Thanks for including this.

 

[AZMSGT]

Thanks @Sisterlimonpot for taking the time to do that. Awesome breakdown on the wetsides and different versions.

 

[Sisterlimonpot]

@Sisterlimonpot , very nice summary of the history of the MP40's. FYI, the old magnet plastic coverings were in fact glued/welded together. You can see the seam in one of my failures in the first post. I also did a mini Reader's Digest version of the differences HERE. Thanks for including this.

Just by skimming the first few pages of that thread it seems we are 2 peas in a pod. If I can engineer it, then I don't need to spend the money for it!! Who says that DIY has to look shade tree?

Back on topic: Ecotech has made vast improvements of their equipment over the years. If there's a way to improve their magnets they aren't going to rest until they get it as close to perfect as they can.

 

[Dkeller_nc]

With respect to the effect of hydrochloric acid on metal (steel, typically 316 stainless) components, I can offer a bit of insight. Hydrochloric acid is a bit of an odd duck when it comes to corrosion of steels. All strong mineral acids, if sufficiently concentrated, can corrode steel, whether high in chromium content (stainless steels) or not. Acidic solutions containing chlorides, however, will not only oxidize the outer layer of steel, but will also cause pitting. Pitting corrosion is especially an issue because of the rapid progression of corrosion in the local micro-environment of the pit.

For this reason, I don't use hydrochloric acid for cleaning of any metal part that's intended for saltwater exposure. These days, that's typically only pump shafts and SS metal screws since almost all construction of equipment for salt water aquariums has moved to various plastics, with the odd titanium screw thrown in here or there.

However, I do use hydrochloric acid at about 1N concentration for glass and plastic items. I limit the exposure to less than 10 minutes because there are a few plastics that are vulnerable to HCl, and one typically can't determine what the plastic is just by looking at it.

I also occasionally use citric acid for removal of calcium carbonate deposits, typically because I've already made the solution for corrosion removal purposes on a metal part (citric, btw, is the go-to for removal of rust on steel without damaging the underlying metal). A tip here is that warming the solution in the microwave before use significantly speeds its action. Obviously, one wants it warm but not hot for the purposes of cleaning plastic parts.

 

[Falcon53]

I've been using citric acid for a long time now because vinegar eats plastic. You find this out the hard way especially with Tunze pumps. It seems to have a really bad effect on the electrical cord in particular. Citric Acid is a real winner for the following reasons:

- It doesn't ruin plastic and penetrate into metal as discussed
- It is safe to handle with bare hands
- It does not smell like vinegar
- It's cheap and more easily available than muriatic acid (not that it's that hard to find)

Since that switch I've no had issues as described here. And as an FYI, if you call Ecotech directly, they will recommend a 90 minute soak in hot water with a dilute acid. 90 minutes is plenty of time.

 

[ReefRy]

I just went to amazon and purchased citric acid. Thanks so much for taking the time to share this.

 

[oneasianguy]

Thanks for the great information. I guess this explained my mysterious swollen magnet. Switching to citric acid.

 

[andyman]

This is a great article and thanks. Its no wonder why my MP60 is going strong for so long. I never cleaned it. I recall finally cleaning it a year ago or so and it got swollen and destroyed (only cleaned 1 side). Now that we know why they are getting distroyed I still wish mfg would use magnets that do not rust like eheim or the red dragon 3 pumps.

 

[Daniel@R2R]

Thanks for the great information. I guess this explained my mysterious swollen magnet. Switching to citric acid.

Sucks when that happens... I'm sorry.

 

[Crabs McJones]

Excellent question. I'm not a gyre person, but believe there are no magnets involved. I'm under the impression that it's a shaft coming from a motor that spins the "basket" impellers. That said, I'd still question whether vinegar could penetrate the plastic portion containing the motor. Keep us appraised if you run into a problem.

Personally, I'm anti vinegar because of what it did to my pumps, and to be on the safe side, I'd switch to muriatic acid....not 30 minutes, but maybe only 10....it works fast.

Came here to ask the same thing. In my gyres, it's all plastic, no magnets and a bearing at the end which is just a rubber bushing with a ceramic center piece. Would these be safe to continue cleaning with vinegar?

 

[Daniel@R2R]

Just ordered 5lb citric acid from Amazon

 

[Victoria M]

Just ordered 5lb citric acid from Amazon

You gonna sell it on the side? lol

 

[Daniel@R2R]

You gonna sell it on the side? lol

Just gonna clean everything everyday! ;Hilarious ;Hilarious

 

[redfishbluefish]

Came here to ask the same thing. In my gyres, it's all plastic, no magnets and a bearing at the end which is just a rubber bushing with a ceramic center piece. Would these be safe to continue cleaning with vinegar?

Mr. McJones, I am unable to definitively answer your question...too many unknowns....type of plastic, thickness of the plastic, whether vinegar is truly the causative agent, whether the seams simply failed... If it were me, I'd play it safe and use either the muriatic acid or the citric acid. If you have young kids, I'd lean towards the citric acid. Muriatic acid is down right nasty, and if you get it on your skin it will give you a severe burn.

 

[Falcon53]

Muriatic acid is down right nasty, and if you get it on your skin it will give you a severe burn.

Indeed.

I had a container of Muriatic Acid in my basement that destroyed everything that was metal nearby. I hadn't really looked near where it was stored for a couple weeks. Somehow the vapors escaped the container, which led to the acid oxidizing everything in it's vicinity.

 

[robbyg]

Hmmm very interesting and informative thread.
I cleaned my MP40 in vinegar for about 3 hours and a few weeks later it had the same swollen magnet issue. I cleaned my Sedra 5000 skimmer pump with Vinegar and for the first time in almost 10 years the magnet swelled and actually jammed in the motor a few months later.

I never made the connection until now.

Thanks so much for saving me some money in the future.

Rob