Danner Mag5 leaky when hot?

I have been running this mag5 non stop for the last 3 weeks that I have had it. Previously I had only run Ehiem pumps in the system, so I am unaware with how Danners should operate.

I check the system ofter, everyday at a minimum, and lately I have noticed a congealing, if you will, of a dried whitish substance around the outer crevices of the Danner. Picture the rear seal, on the outer lip of the seal where the top of the plastic meets there is a white substance. On the front around the face plate, and again seeping out of one of the screw holes. I have not removed the face plate, nor has this pump been dropped or jarred. It does run very hot, and I have placed a small quiet 80mm fan blowing across it to prevent heat build up.

Questions:

1. Has anyone experienced this?
2. Can this be corrected with marine goop/sealant?
3. Is this leakage caused by heat or the WW eating at the sealant inside the pump?
4. With whatever it is seeping out the back of the pump, is there a possibility of electrical shortage/letting the secret smoke out?

Having just ordered a new Typhoon res and 2 more 120cm quiet fans, I will be draining and chaining the configuration of the lines. I figured while I was doing this I could repair the pump if necessary.

Thanks

I wouldn't waste my time repairing it. It is an exercise in futility. Mag pumps are notorious for leaking when run externally, ask anyone in the aquarium hobby. I would replace it as you will spend more time and money than it is worth trying to repair that pump. Go back to Ehiem's!

Pull the front cover and seal it with silicone. I use aquarium sealer from home depot(about $4). Put a bead over the o-ring and re-install the cover. While you have the cover off inspect it for cracks. See if this stops any buildup around the rear cover.

I don't know what exactly Water Wetter is, but it sounds to me like it causes many problems with eating away at seals and other important stuff. I stick to distilled water and antifreeze.

I'm having issues with something coming out of solution (Water Wetter + distilled water) and seeping through the threads at my reservoir barbs. Sounds like you have a similar problem; I attribute it to the Water Wetter.

I had to use sealant around the propeller housing in my mag, along with the o-ring. Never had a leak from the pump and I had mine running for over a year.

"I'm having issues with something coming out of solution (Water Wetter + distilled water) and seeping through the threads at my reservoir barbs. Sounds like you have a similar problem; I attribute it to the Water Wetter."

I assume the barbs are plastic?

CGR said:

I assume the barbs are plastic?

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Nylon barbs / polyethylene reservoir. I used Teflon tape, and now it's clear that Teflon tape is inappropriate for this use. I should have applied a paste of some sort.

I've been using water wetter in my watercooled system for 3 years now without any leaks. But I'm using an Eheim 1250 pump and I made my own reservoir out of a 4 X 4 X 4 plastic outdoor electrical box and I use threaded brass 1/2" pipe coming out of it and brass 1/2" hose barbs. The only problem I've had with my system is that since I used silicone tubing instead of vinyl or tygon, I have to replace water every once in a great while since silicone lets water molecules escape slowly, kind of like a helium filled balloon. And I also drilled a tiny hole in the fillup cap on the reservoir to keep the system from pressuring up, which also contributes a little to evaporation loss. But there are no leaks at all from anywhere in my pumps or res or tubing.

But I can see how water wetter could contribute to leaks, since it is a surface tension reducer.

aaronjb, you might try going down to your local Lowes or Home Depot and seeing if they have any brass hose barbs. That might give you a better seal into that poly reservoir with teflon tape.

The aquarium sealer is very good for sealing barbs. You only need to handtighten the barbs for them to seal. The Mag pump housing is very easy to crack if you overtighten the barbs. I have a Mag 3 that has been running well over a year without any leaks once it was sealed.

I used WW a long long time ago when I cooled my Athlon 750. DIdnt like it all too much. I switched to Purple ice after that then to Hydrx later on.

you could try RTV on the seals as well.
btw. 17 years in the aquarium hobby and the Mag's don't leak much more then any other pump in the price range extrenaly.. (actually its one of the best for that price range)

fade2black said:

I wouldn't waste my time repairing it. It is an exercise in futility. Mag pumps are notorious for leaking when run externally, ask anyone in the aquarium hobby. I would replace it as you will spend more time and money than it is worth trying to repair that pump. Go back to Ehiem's!

Click to expand...

I am very active in the aquarium hobby and on the largest aquarium board, www.ReefCentral.com. I agree that Mag pumps do leak when used externally. However, the fix is very easy and has already been mentioned. Remove the volute (front cover) and put a small bead of silicone on the o-ring. Replace the cover and let this dry for 24 hours. ANY silicone will do. Since this is not for an aquarium, there is no reason to spend the extra money on aquarium silicone. Heck, people in the aquarium hobby do not spend the extra money on aquarium silicone.

Mag pumps are known for their reliability, save for the leaking issue. I would just fix this and not spend the money on another pump. Hell, a tube of silicone costs about $1 and the caulking gun is less than $5.

Fade2black, are you the same fade2black from ReefCentral?

As to the questions...

Vampiregabe said:

1. Has anyone experienced this?
2. Can this be corrected with marine goop/sealant?
3. Is this leakage caused by heat or the WW eating at the sealant inside the pump?
4. With whatever it is seeping out the back of the pump, is there a possibility of electrical shortage/letting the secret smoke out?

Click to expand...

1.) Yes, anyone in the aquarium hobby that has tried to run these externally. This is no longer recommended in the aquarium hobby.
2.) Yes, but you run the risk of never being able to remove the cover and do repairs. Use silicone.
3.) No, Danner never intended these pumps to be used externally and did not design them to do so. The seal is inferior to pumps designed for external use. The seal is EPDM and can withstand almost everything you could throw at it, save ozone. I don't think anyone here is trying to disinfect their waterblocks.
4.) Hmmm.... This is not good! There should be nothing leaking out of the back of the pump. The motor is sealed with epoxy. It could be that the motor is overheating and the epoxy is breaking down. If this is the case, then yes, there is a possibility of a shortage. Again, these pumps were never meant to be used externally.

Ok. I took the face plate off and found that the lower right barb sheered off. I mean slick as a baby's bottom sheered. The screw, when I loosened it, apparently was so tight (from the manufactuerer) that it took the barb with it. So now there are three barbs holding the face plate on.

I have used about a 1/4 tube of marine goop to reseal this thing. Test, leak, seal new leak, let sit to dry, test, etc.

I still have an older ehiem that I can use, but I would rather use the mag5 as the ehiem can't push through the cpu and 2x gpu blocks. Ugh.

As for the leak from the rear of the pump, apparently it was just water collecting from the drip in the back collecting in the back. I guess.


As for the WW, I had previously run the system for a long, long while with WW and never had any problems, and wanted to know if the mag5 was different.

MarkS said:

Fade2black, are you the same fade2black from ReefCentral?

Click to expand...

Yup, same one. I hate Mag pumps too

lol.. Ive probibly have less then 100 posts on RC.. almost 6K at aquariumadvice though

@Vampiregabe.. could you snap a pic. of the problem with your pump?
you might be able to drill it out and replace it.

Ok. Well after figgiting with this thing, I have swapped out the Mag5 for the Eheim 1048.

I expected a large increase in temps, and I am happily supprised that temps have actually dropped. This of course could be do too the addition of 2x 11CFM 120mm fans added to the front of the rad. There are still 2x 6cfm 120mm fans on the rear pulling air through.

Temps are @44C on an X2440+ @ 2420
Temps on the 7800GTs reads below 40C

So overall I guess it is ok.

Suprised with the temps though. Wouldn't the Mag5 with the higher flow (500GPH) give better results than the Eheim (600LPH)?