View Full Version : Tunze 9410 dc skimmer pump noise

01/25/2017, 06:27 PM
Dear forum

I purchased the aforementioned skimmer after reviews were favorable and I am sure what I am experiencing is new pump issues but would like to check a few things that are not in the troubleshooting section of the manual.

1. The skimmer pump is extremely noisy on initial start up (1-2 seconds) before any air draw and when running with no air going into the pump (pinching the airline)

I removed the pump from the body, removed the volute cover and inspected the impeller, ceramic bearings and rubber shaft caps, all smooth and ok.
the skimmer sits in 210 mm of water and the pump is firmll secured to the body, I have also inverted the pump to let any air escape.

2. As air is allowed to mix the noise reduced significantly but and audible hum is still heard and this increases as the power level to the dc pump is increased to up to 100%.

There is little if any noise coming from vibration it all eminates from the pump.

My question is; Is a loud noise expected from this pump when there is only water passing through it? It is a really loud noise akin to a hammer drill through a wall but as stated when air is mixed there is a significant difference.

Thanks, I would like to state that I really like Tunze products and have had nothing but favorable experience in over 15 years using the products.

01/26/2017, 06:28 AM

I just got the TUNZE 9410 DC skimmer today.
I Will post my observations later.

BR, Goran.

01/26/2017, 08:41 AM
Is this with the pump stand alone or connected to the skimmer? Connected to the skimmer you will get a loud noise from water being drawn into the air intake. It will generally be louder with only water but it should not be so loud, I suspect one of the bushings is not seated. Also, keep in mind that pump will likely never be run over 50% on the skimmer.

01/26/2017, 08:52 AM
The noise is apparent both connected to the skimmer and when free from the skimmer body when there is no air allowed into the pump. If I pinch the air line the noise happens and when released and the air rushes back in and the noise is much much quieter.

How do I go about seating the bushings....

By the way it is skimming very well and it has been less than 24 hrs, the pump power is a shade below 50%.

Thanks for your reply Roger, you are a stalwart of the hobby.

01/26/2017, 09:37 AM
One is in the impeller cover and you can just push it in with your finger. The other is at the bottom of the pump under the impeller, this is the one that tends to come loose in shipping, you will usually need a dowel or pen or something to push it in.

01/27/2017, 08:16 AM
To follow up I took the pump apart and disassembled it carefully.
The bushes seemed fairly secure. I did try the pump in water with no air and the noise was there but not nearly as loud. When the skimmer was fully assembled it began to run much quieter, to the point that it is not audible over other tank equipment.

I don't know if it will be permenant but I hope it stays quiet.


01/27/2017, 09:22 AM
I think it will, my guess is there was a bubble trapped in the top and opening it and reassembling it cleared that out. Normally the cooling duct will purge any trapped air but it can be airlocked.

01/29/2017, 09:48 PM
Skimming like a champ now.

01/30/2017, 09:17 AM
Great news! Thank you!

09/18/2017, 06:26 AM
Dead set, after 8 months continuous running THE best reef purchase I have ever made.
Affordable, set and forget, easy to clean, silent (i know)

60 to 100 gallons this is the skimmer for you!

09/18/2017, 09:30 AM
Thank you!

11/11/2017, 02:03 AM
Roger - I am having the same problem with noise. I put the skimmer in the sump this week (brand new). It started making the squealing / grinding noise after just a few minutes, If i unplugged it and plugged it back in it would run ok for a couple of hours then start back with the noise. Now, it is non stop to the point where it sounds like it is about to siege up. I checked the bushings as you had prescribed and they are sited fine. I have contacted MD to exchange the pump. But, i thought I would check back and see if there was anything else you would suggest. I think I have a defective pump. I am very disappointed with this situation so far.

11/13/2017, 08:10 AM
What is the operating depth? If the bushings are fully seated and the skimmer is in a depth of 6-7" the most likely culprits will be the air intake housing (bottom of pump with air hose attachment) is the wrong one, or the impeller has some blemish. Squealing will come from a bushing being dragged, usually because it is loose, or from too much air being taken in (wrong intake). How long have you had it?

04/08/2018, 07:48 PM
I just purchased the Tunze 9410 2 days ago, immediately after installing I'm getting a horrible screeching noise from the pump. If I pinch the airline-tube the noise subsides for a few minutes then continues, the noise is unbearable.

04/09/2018, 09:00 AM
Please PM me your info and I will get you out a replacement impeller.

04/09/2018, 11:12 AM
Please PM me your info and I will get you out a replacement impeller.

You think the impeller is the issue? I just purchased the skimmer 2 days ago.

04/09/2018, 11:21 AM
Yes, it is the wrong one and it rubs the housing.

05/22/2018, 06:23 PM
Skimmer still going great guns still best purchase I have made.

05/23/2018, 08:15 AM
Thank you!