Sump questions.

[pcfriedrich]

Just got a sump up and running for the first time. Up to this point, I've only use HOB power filters. I bought it used, came already installed in the aquarium cabinet. It is running a Little Giant Little Giant 3-MDQX-SC model pump ( http://www.pexuniverse.com/little-giant-3-mdqx-sc-aquarium-pump-581507 ). 135 gallon tank.

First, the pump is loud. Way louder than I expected. not as loud or high pitched as a vacuum cleaner, but still a similar constant hum. Did I have too high expectations? I still don't have the doors installed on the cabinet, and its quieter when I set them against the openings, and some insulation would probably make it tolerable, but my concern is that the noise means the pump isn't working efficiently. There is also air bubbles coming out of the return, so that makes me really think its not working as efficiently as possible. Maybe the pump isn't fully primed? The outflow is split. it has one return going to the tank, and the other goes to a protein skimmer. I have the valve leading to the protein skimmer closed, though, as I plan on running freshwater. Another thing that kind of annoys me already is the overflow. The box only fills about a third of the way (the overflow drain is a vertical piece of pvc with horizontal notches cut all the way up). This leads to an annoying "waterfall" sound.

Any advice on fixing or correcting these issues would be appreciated. I'm pretty psyched about finally having a decent size tank going, but the constant hum, "waterfall" sound and air bubbles coming from the pump return have me concerned I won't be able to tolerate this filtration system very long.

The system sat in a garage for several years before the previous owner decided to sell it.

Thanks for your advice.

 

[duanes]

I'll speak to the hum, and let others the gurgle.
Some pumps are louder than others, and will always hum, but I find putting an aquarium sponge under and/or along side the pump and its plumbing helps, especially if the pump is touching the side glass.

I have started replacing Mag Drives for Laguna pumps because they have less humming noise.

 

[pcfriedrich]

Thanks. That's what I was kind of thinking about. Mine is an external pump, but surely pipe insulation, some insulation around the pump itself, and insulating the cabinet with some foam would help. This is just way louder than I expected. I'm in the next room and can hear it...

 

[pcfriedrich]

I put a larger diameter and longer pvc pipe over the drain pipe, as well. That allowed the water level in the overflow box to rise, reducing that sound. I just placed it over, didn't caulk it down or anything, so water is now running under and over that pipe. No flooding yet...

 

[pcfriedrich]

So air bubbles out of a sump return are normal?

 

[duanes]

Air bubbles can mean the pump is cavitating, but not always, because depending on pipe size, pipes are not always completely full of water.
If your pump sounds like its crackling (almost sounds dry), that is the sound of cavitation, which is the collapsing of bubbles around the impeller. Cavitation can pit, and ruin an impeller. The collapsing bubbles can come from air disassociation with the water.
Could be its not primed well enough, or the impeller shaft is wobbling, if it is cavitation.
There is plenty of cavitation (and other useful knowledge) info on the awwa website (American Water Works Association).

 

[pcfriedrich]

Could cavitation be caused by a valve on the return that, say, is stuck? It is halfway open, but the handle is broken. I can't open or close it any further. I was thinking it was possible the bubbles are caused by the existence of a vacuum in the system. That is just a guess. I work in medical field and I know if you have a syringe of fluid, cover the end and pull back on the plunger, you will get an air bubble from the low pressure, even though no outside air entered the chamber.