Noisy Iwaki...user error?

[fishy929]

I just finished setting up my upgraded 90G in a dedicated "fish room" in my house. I worked very hard at limiting the noise with the overflow and sump and am now battling it out with my Iwaki 40RLXT.

I thought it would be a good idea to bolt it down inside the tank stand with 1/4 inch rubber matting under the feet. But the humming sound is too much to handle. Would it be a better idea to move the pump out of the stand and bolt it directly to the carpeted floor in the 6 1/2" space behind the stand, or will it make any difference?

I know people swear that the Iwaki's are quiet :roll: Any help or suggestions with piping this down a bit would be greatly appreciated.

Thanks!

 

[Len]

Quiet is really a relative term. However, the 40 series on up have cooling fans and thus are noiser then the 30 series. I'm guessing since you have it bolted down with rubber matting, it's probably the fan noise that you're hearing. You might want to see if you can get a 30RLXT as an exchange.

 

[Anonymous]

When bolting pump to a sounding board (tank stand), make sure you:

1, use oversized hole on the board for the bolt to vibrate

2, use rubber washers between the pump's feet and board, and on the other side of board to limit the amount of vibration.

That is, bolt's head->pump's feet->rubber->wood->rubber->nut.

and
3, do not overtight the nut

 

[fishy929]

Len,

I was actually thinking about getting a bigger pump! I was not aware of the additional fan in the 40 series pumps. My plans were to turn over the total system volume (90g +20g sump) at least 10x, but more would be better. The 30 series puts out 960gph at 8' head or something like that. Would that still give me plenty of turnover for my SPS's?

 

[fishy929]

Dupaboy,

Thanks for the tip. I did not use rubber on the backside and I DID overtighten. Although, I loosened them up a bit last night. I put my ear to the acrylic topside and boy is this thing going to be loud for the fishes... My thought was that my cabinet is acting like a bass tube or something and that getting it out of there would help.

I'm not expecting complete silence, only to not be able to focus on the sound from the second floor of the house...

 

[reefland]

I lined the entire inside of my 180 stand with 1 inch thick soft foam often used to line the floors where children play. They come in interlocking squares. I seem to recall Home Depot selling them. Worked well keeping my Iwaki MD70RLT pretty quiet. And it is water resistant.

Also - don't hard plumb everything. I found using more flex hose than rigid PVC helped. I haven't tried flexible PVC yet. I'll be using that on my next setup.

 

[fishy929]

Reefland,

That sounds like a great idea...no pun intended I unbolted the pump last night and it did seem to help. I'm not getting near the vibration in the actual tank. I still have it setting on some neoprene matting. I will pick up some of the foam when I go to get my sand today. If the squares are small enough, maybe a small foam box with the back exposed would quiet it down further and not hinder heat transfer so much.

I'll give it a try and report my scientific findings :roll:

 

[Anonymous]

I am not too sure if a foam box with only one side open is such a good idea... IMO. The pump generate lots of heat, and if you put nice insulation around it, it will malefunction pretty often.

The issue here is the direct transfer of vibration from the pump to the stand and amplification due to the "sounding board" effect. A vibrating spring does not make much noise, but if you put it on a sounding board (say, a piano or a guitar), it can make quite a difference. The foam and others trick is only effective for noise that is already "in the air." You need to nail it before that stage.

 

[fishy929]

Dupaboy,

I think that I have addressed the vibration issue when I removed the mounting hardware. To test this, I listened for the sound while the pump was sitting on the matting, and again with the pump lifted off the surface. There was little to no difference in the sound. The sound is greatly reduced, however, when I place a pillow to cover the back of the stand. Unfortunately, they are decorative pillows and I would be in big trouble if my wife knew they were anywhere near the tank It was an experiment anyway.

I don't believe I am getting vibration to the flex hoses connected to the pump either. At least nothing detectable. So, I am thinking that teh humming is just being amplified from being in a large open area. So, maybe closing off the area, even partially would reduce sound. The problem then becomes, as mentioned before, the issue of providing enough heat transfer to keep the pump cool. I am very impressed, by the way, by how cool this pump runs.

Any safe suggestions?

 

[Fishbreath]

I just had a similar experience with a new Iwaki MD30RXT. Many on the board report this pump to be quiet but mine was not. I discovered the noise was coming from the intake, transferring through the water to the sump where it then resonated like crazy. Way too loud. The distance from the pump intake to the sump was only about 8" through a piece of 1" dia vinyl tubing, which was a direct shot for the propeller noise to propagate into the sump. I lengthened the intake tubing to 5 FEET, making a single loop aroung the pump mostly inside my tank stand. Some of the loop had to go outside the stand between the stand and the wall (can't see it from the front of the tank) to avoid kinks. This now acts as a muffler and the sump is quiet. I'm still getting that old aquarium pump hummmm that I wish wasn't there, but no vibration noise in the sump and this pump solved my temperature problem. I'm not getting any temperature rise in the water from this pump. Question for other MD30RXT owners... does your pump hum or is it silent?

 

[Modo]

I have an Iwaki as well and a Blueline. Both pumps together made a hell of a racket!

I fixed this by bolting both to a 1/2" piece of plywood cut down to hold both pumps. I used styrafoam between the board and pumps and bolted the two down. Then I placed this board on 3 pieces of "egg-crate" foam that people use on beds. This stuff is about an inch or so think, but really compresses.

This allowed for a solid base for the pumps, but the vibration is absorbed as the board they are bolted to "floats" on the foam.

I got this foam from the bedding aisle at Target for $6 bucks. It's a huge queen sized foam cushion that I can cut up and use. I'm thinking about adding it to the inside of my stand as well to abosrb some noise. I wrapped my SQWD with it too and can't hear a single rattle now when it switches.