Black residue coming off pump impeller.

[awfl_wafl]

I purchased a used Cor-15 pump. Pump works, but after disassembly and cleaning, I discovered some rust spots on the impeller magnet, and when cleaning it off, noticed black residue keeps coming off on my fingers. No matter how much I scrub, it doesn't stop coming off. I'm guessing I need a new impeller? Should the rest be ok?

 

[BanZI29]

It looks like the impeller was rubbing on the inside. replace the impeller for sure but use a bottle brush or something to see if material comes off the walls of the drive.

 

[ReefHunter006]

Poster above me is likely right.

Something worth checking is if the original owner or you use Aqua Forest mud. The basalt is magnetic and typically leaves residue like that on my equipment. Never been a significant issue.

 

[awfl_wafl]

It looks like the impeller was rubbing on the inside. replace the impeller for sure but use a bottle brush or something to see if material comes off the walls of the drive.

I've cleaned the inside of the housing well, and no black residue or anything else is coming out of there.

 

[awfl_wafl]

Poster above me is likely right.

Something worth checking is if the original owner or you use Aqua Forest mud. The basalt is magnetic and typically leaves residue like that on my equipment. Never been a significant issue.

Thanks for the tip. I tried cleaning it again, this time using rags to kind of squeegie off the shaft. Eventually the the black residue went away. I'm going to soak the impeller for a bit and see if any rust or black residue shows up again.

 

[awfl_wafl]

After 24 hours of soaking no Rust or black residue. I'm going to go ahead and use it, but just keep a close eye if anything takes a turn for the worst.

 

[awfl_wafl]

Interestingly enough, after adding the pump to my tank, my salinity reading dropped 1ppt.

 

[ReefHunter006]

Interestingly enough, after adding the pump to my tank, my salinity reading dropped 1ppt.

Likely micro bubbles finding their way to the probe would be my guess.

 

[awfl_wafl]

Likely micro bubbles finding their way to the probe would be my guess.

That was it. Learn something new everyday.