Pump installation question

[GlassReef]

As part of my new build I have installed 2 Dart Gold pumps. They both take water from the sump via 2" plumbing:

Because the Darts seemed very loud, I started investigating the problem. I found that if I disconnect the pumps from the sump, I can barely hear them. As soon a I hook them back up to the sump a loud droning noise resumes. I think the sump (3/8" acrylic) is resonating. The noise is very annoying.

Has anyone had this type of problem before? Any solutions?

Thanks

 

[mflamb]

Tom, I like to have a little more plumbing between my sump and pump. I use slip bulkheads and use flex pvc for the first piece of pipe connecting to the bulkhead.

 

[GlassReef]

Do the think the rigidity could be the cause of the noise, Mike?

 

[wmilas]

*Puts on engineering hat*

The problem is that there are two pumps. The pumps rotors are turning at slightly different speeds. When this happens you end up building a secondary wave that transfers through the attached plumbing and the sump just amplifies the wave (like a sounding board)

The only way this is going to stop is to put an isolation collar or segment on at least one, but preferably both pumps. A small segment of spaflex would probably do the job.

Hope this helps.

 

[mflamb]

<a href=showthread.php?s=&postid=14093112#post14093112 target=_blank>Originally posted</a> by GlassReef
Do the think the rigidity could be the cause of the noise, Mike?

I think that could be the cause. That's why I started using the flex pvc. I have found it to be more pronounced on acrylic sumps.

One other thought I had was to add vertical structural support inside the sump in between and/or both sides of the bulkheads, in the form of 1 inch strips of acrylic from the top to the bottom.

 

[Untamed12]

In the photos, the sump is empty and the pumps are not connected. Do you have this problem with the sump full of water and everything in place?....or did you just do a quick sound test with everything dry?

I assume that water would quiet everything quite a bit.

 

[polywise]

Untamed12,
very forward thinking ++

 

[KRASHPD]

I think untamed is on the right track. I had a very similar setup to yours with two sequence pumps next to each other on the stand and only a couple inches apart. Once the sump was full of water and live rock rubble and the pumps were on the foam mats, the vibration was cut way down and there was very little noise. Here are a couple pics:

 

[mflamb]

<a href=showthread.php?s=&postid=14095405#post14095405 target=_blank>Originally posted</a> by Untamed12
In the photos, the sump is empty and the pumps are not connected. Do you have this problem with the sump full of water and everything in place?....or did you just do a quick sound test with everything dry?

I assume that water would quiet everything quite a bit.

Page 12 of Glass Reef's build thread shows the tank/sump running with water.

 

[GlassReef]

Thanks for the great ideas, everyone. The noise does happens with only one pump running. I think I'll take everyone's advice and add some Spaflex to each connection. In addition, I'll add two strengthening strips of acrylic to the end wall of the sump.

I'll report back.

 

[tomasz]

I agree that water should quiet everything down. But, the quastion I have is how big is the sump and why are there two pumps on it? That is a lot of flow to go thru the pump.

 

[GlassReef]

<a href=showthread.php?s=&postid=14098231#post14098231 target=_blank>Originally posted</a> by tomasz
I agree that water should quiet everything down. But, the quastion I have is how big is the sump and why are there two pumps on it? That is a lot of flow to go thru the pump.

The sump is 75gal. One pump is for the display tank - the other is to supply a fuge and a frag tank.

 

[tomasz]

<a href=showthread.php?s=&postid=14098257#post14098257 target=_blank>Originally posted</a> by GlassReef
The sump is 75gal. One pump is for the display tank - the other is to supply a fuge and a frag tank.

How big is the display tank and frag tank? That will be a ton of flow thru 75g sump. Did you look at installing one bigger pump for everything?

 

[GlassReef]

Display = 375gal
Frag = 75gal
Fuge = 75gal

 

[tomasz]

<a href=showthread.php?s=&postid=14098303#post14098303 target=_blank>Originally posted</a> by GlassReef
Display = 375gal
Frag = 75gal
Fuge = 75gal

Here is what I would do:
Go with bigger pump (less noise then two pumps), put a Y on it with ball valves and regulate the flow any way you like it. Get an extra pump for emergency if the first one failes.
I think two darts for your sump are way to much!!! Did you already try to run water thru the whole system with both pumps?

 

[GlassReef]

<a href=showthread.php?s=&postid=14098349#post14098349 target=_blank>Originally posted</a> by tomasz
Did you already try to run water thru the whole system with both pumps?

Yes - didn't seem to be a problem - except for the noise.

 

[tomasz]

<a href=showthread.php?s=&postid=14098368#post14098368 target=_blank>Originally posted</a> by GlassReef
Yes - didn't seem to be a problem - except for the noise.

How much water drains out of the sump?

 

[GlassReef]

Not sure I understand what you mean. In case of a power failure the sump fills with 30 gals from the other tanks.

 

[Elliott]

I had a similar problem with a CL using a big Iwaki 1/2hp MX250 pump. The pump sits in the garage and plumbed through a wall to the tank. I was able to dampen the vibration by adding alternating spas flex and rigid pvc and extending the length of the plumbing. It's hardly audible now at the display.

 

[polywise]

ever think of putting a strut (piece of PVC ) putting minimal preasure between the two pipes coming from the sump, prior to the pumps to dampen the noise?