Best ( most quiet ) method to run a return?

[shoggoth43]

I've got an older Maxijet utility pump I'll be replacing with a DC pump. In the meantime I'm curious as to the best way to make the return as quiet as possible.

I have the pump on a silicone trivet. From there I will be going with 1.25" or 1.5" pipe. I planned on running the pipe from the pump to a pipe clamp ( lined with foam or neoprene ) and then up to the top of the tank. I figured I could use one of the repair compression pipe fittings behind the tank glass as it would allow for misalignment and hopefully decouple any noise from the pipe as well as act like a union fitting if I need to take things apart later. The return over the tank rim would probably be just a couple of 90s ending just under the waterline. I can use another bit of trivet or silicone tubing between the pipe and the edge of the tank.

I have some 1" silicone tubing, but I'd prefer to avoid the restriction from the pump to the tubing and then to the pipe if I can. It may just be that the DC pump will make this a pointless exercise but the AC pump I have in place does have a hum I'd like to minimize.

How do most people handle clamping pipes to the stand to minimize the noise transfer when they use >1" pipe?

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S

 

[Smo]

You can get silicone tubing in larger diameters. I use a section between my return pumps and hard plumbed manifolds to dampen vibration.

 

[shoggoth43]

Where did you find 1.25" or 1.5" silicone tubing? I didn't find anywhere that didn't require a large quantity to be purchased.

 

[Dual40IM]

Where did you find 1.25" or 1.5" silicone tubing? I didn't find anywhere that didn't require a large quantity to be purchased.

I think Bulk Reef Supply sells it by the foot.

 

[Smo]

I think Bulk Reef Supply sells it by the foot.

I thought so too, but a quick check shows they only sell it up to 1” ID.

 

[ca1ore]

A good quality DC pump isn’t likely to transmit much vibration - my vectra does not. Any vibration is likely to be via the pump body, so your silicone pad is the best thing to do. Buzzing from pipes is usually a result of movement. Clamp them down tight and the mass of the stand/tank will fully dampen any noise. I never bother with a silicone translation on the return pipe, though I do use flex PVC which has some inherent damping properties.

 

[jda]

If you have a low head application, then the low-RPM DC pumps can be quieter since they are not spinning as much. If you have high head, then it might not matter and you might have a mild hum with whatever you get. I think that you are doing the best that you can do other than suspending the pump in the water so that the vibration never touches the glass - of course, this required a custom holder also with some silicone contact points.

 

[shoggoth43]

I checked BRS and other places for silicone tubing. They go up to 1". I could PROBABLY get it to stretch over a 1.25" hose fitting but I'd be concerned about it tearing at some point and given I'm looking at a Varios 6 pump for a good price locally, that'd be potentially quite a bit of water blasting everywhere. There are some food places that sell bigger tubing but I'd have to buy quite a lot at a pretty hefty per foot cost so that's not really an option.

My application is maybe 5' of head max, and pretty much going to be a union on the pump maybe a 45 or two to get out of the stand, that compression fitting or another union if needed, and the two 90s over the top using 1.25" or 1.5" pipe to keep the velocity down so I don't ever risk a sandstorm. It's a pretty low static head pressure scenario and I'd be surprised if it amounts to much more than the equivalent of 10 feet of pipe. Velocity would max out around 6 ft/sec with the smaller pipe and closer to 4 ft/sec with the 1.5" pipe and I don't plan on running it at full bore anyway so friction head should be pretty much a non issue.

I think I'll go with the trivet and then try and clamp the pipes to the stand with a foam insert in the clamp and then see if I can get over the tank rim with it either not touching, or with a silicone touch point for stability. That should hopefully limit the opportunities for vibration to creep in.