Mag 12 owners question.

Geoff · 11-15-2002, 09:17 PM

I just bought a mag 12, because I thought it was going to be quiet. The motor itself seems very quiet, but I seem to get a lot of cavitation noise. Is this normal? How quiet are all of your mag 12's? This is going to be one of my CLS pumps. Are there any other pumps that are quieter? This is going to be one of those in the corner CLS's, that are just above the water line. So far my wife loves the way the tank is so far, but this pump is to noise for her likes. I also tried a ViaAqua 4900, that was a little noiser but not be much. Are all of these pumps loud.

Thanks,

G~

Minnreefer · 11-15-2002, 09:32 PM

I have not had too much luck witht he mags as an external pumps

, They are great interenal pumps. You might be able to put a LOT of sticky foam on the pump to help quiet it.

HTH

Jon

Stang69 · 11-15-2002, 10:32 PM

Some folks recomend a cut out piece of mouse pad also.

Jeff

cyberchef · 11-15-2002, 11:18 PM

I have a Mag18 and it quieted right down when I slipped a piece of foam pad under it. Before that iot was vibrating against the wood stand.

JennM · 11-16-2002, 09:19 AM

The larger mags come with a piece of foam -- did yours? check the box if you've still got it- it should have a piece of foam about the thickness of a mouse pad.

I've got a Mag 12 as my return in my 120 at the shop and I don't notice any noise- but then again, it's one of the SMALLER pumps running there -- all the bigger ones would drown it out

Jenn

XeniaPhobe · 11-16-2002, 10:36 AM

Quote:

Originally posted by Geoff
....... but I seem to get a lot of cavitation noise.
G~

Is it cavitating? Blowing any bubbles that you can see? If so then that would explain a lot. How is the intake to the pump plumbed and where in relation to the water feeding it is it sitting? Cavitation noise will be quite different than humming from vibration.

Geoff · 11-16-2002, 11:46 PM

Thanks for all of the replies. It was cavitation noise and the fix is back pressure. Apparantly these pumps do not like to be run full out without any back pressure at all. The secound I put a valve on the output and closed it just a little the pump just quieted right down. The foam bad will work great for the remaining 60hz humm.

Thanks,

G~

tdwyatt · 11-17-2002, 10:29 AM

Quote:

Originally posted by Geoff
It was cavitation noise and the fix is back pressure. Apparantly these pumps do not like to be run full out without any back pressure at all. The secound I put a valve on the output and closed it just a little the pump just quieted right down.

Heh!

I have two in the prop system sump, one to run the skimmer, one to return water to the tank. Neither one has much head, but the skimmer one does run a beckett injector. Both of them are quieter than the Halide tar ballasts were, only have a very low humm.

Can't wait to get the new icecaps MH ballasts up and running, it will be nice to not have that drone going on in the background...

Thanx for the heads up on the back pressure issue.

XeniaPhobe · 11-17-2002, 10:35 AM

Quote:

Originally posted by Geoff
........The secound I put a valve on the output and closed it just a little the pump just quieted right down......

That may have just reduced the amount of air being sucked in to the pump enough to quiet it down. If your happy that's good but your pump input plumbing could still have a small air leak not allowing you to get full throttle from your pump. I originally had the same problem from a LG pump. Thought "no way" was there any chance I had a leak.... but I did

JMO.

Geoff · 11-19-2002, 10:38 PM

It still seems to be making more noise than it should. I may see some very, very, very small bubbles coming out of the output. I have the pump suspended just above the water line with a 3/4 to 1" adaptor into the water. Then I have a 1" strainer on that. I have used pipe tape in the threads to the adaptor so I would think that that is not where the leak is. I took the pump off today and it could be the seal, I saw some salt creep around it.

JMO-where and how did you finally seal your leak. Does the leak have to be on the input to cause the noise?

If I submerge the pump I can still hear the cavitation noise.

I will keep trying,

G~

Geoff · 11-19-2002, 10:51 PM

Thanks for all of the replies. It was cavitation noise and the fix is back pressure. Apparantly these pumps do not like to be run full out without any back pressure at all. The secound I put a valve on the output and closed it just a little the pump just quieted right down. The foam bad will work great for the remaining 60hz humm.

Thanks,

G~

XeniaPhobe · 11-19-2002, 11:14 PM

Quote:

Originally posted by Geoff
I have the pump suspended just above the water line with a 3/4 to 1" adaptor into the water..............
If I submerge the pump I can still hear the cavitation noise.

The first statement sounds like the problem but the second kind of throws a brick at my theory

If I read you correctly, the pump input is above the water, all the time. These pumps should always be gravity fed. In other words, the input absolutely must be below the water level or you will have this problem and the pump can be damaged. They are not made to "draw" water, but push it. Another reason why when you throttle these back it should always be done on the output side.
However, if you submerged it, then that should have solved the problem

Maybe there is some air bubbles in the area where you submerged it?

Mag 12 owners question.

Re: Mag 12 owners question.