View Full Version : Jebao DCT Speed Varying

01/25/2017, 08:54 AM
Hi all,

I've got a freshwater system with a Herbie style overflow. Feeding it is a Jebao DCT pump (I forget which size).

I can't keep the water level in the overflow constant. I'm trying to add CO2 to this system (live plants), so keeping the water level in the overflow is important to reduce degassing.

The pump makes a slight humming noise, and I can actually hear it change frequency once in a while. Is this common with the DCT pumps? It's driving me insane!

It's not my power because I have 2 other pumps running Herbie style overflows and they don't have any issues at all. They're not the DC pumps, but I'd think a DC pump that's only running at half power should be more capable of handling power fluctuations.

Anyone have any ideas to try? Or is this pump just not going to work for this setup?

01/25/2017, 08:54 AM
I actually just thought of one idea. I'll try plugging the pump into a different power strip tonight to make sure that's not the issue.

01/25/2017, 08:58 AM
might also need to clean the pump. I have a DCT pump running my skimmer and it makes no noise at all. as for keeping the level in the overflow, this either has to do with getting the flow tuned in or maybe the pump has an issue and is slowing down and speeding up. I would pull it out and give it a good cleaning and see if it helps.

01/25/2017, 09:04 AM
Yeah, I'll get the system tuned just perfectly and that night I'll wake up to either the emergency pipe trying to start a siphon or the siphon pipe sucking air. It's crazy frustrating.

It's only about a month old, but I guess that could be worth a try too. I'll see if I can get myself to clean it this weekend.

Also, when I say it makes a hum it's a very very quiet hum. It's close to silent. I think the hum may actually be from the controller. It's not noticeable unless I listen for it or the frequency suddenly changes.

01/25/2017, 09:12 AM
I have a DCT 4000 and I have noticed about after a month it slowly starts losing power to push water. I take it out and clean it and then back to normal. It's not really a big deal to me to clean it every month, only takes a few to clean it.

01/26/2017, 06:03 PM
the pump should not be changing intensity on it's own. the controller and power supply should be silent the pump may make a slight hum but it's a constant hum. If the frequency of the hum changes on it's own, that's your problem. they have a one year warranty, maybe take advantage of that.