Advice on powerheads
 

I have 2 Hydor Koralia 4 (for almost 1 1/2yrs) and they are both "rumbling" like a high vibrating sound that would drive you nuts. I phoned J & L and they thought it might be the impeller. Nobody carries this particular part that I know of, so I ordered them from Aquariumparts.com. Changed the impellers, cleaned the powerheads, put them back together securely and tested them only to find out one of them is still making that rumbling sound (if I was a fish or a coral - I would go insane!). What do you think it could be? Should I get new one(s)? Please help. Thanks!

for the price of new koralias I would just buy some new ones

you have to remember that it is a rotating part and it could have honed a larger bore over time and what your hearing is the impeller vibrating in the housing as it rotates. Or its the motor just getting ready to fail. either way just use them for mixing/spares imo

Get a new one especially if you are running the older model Koralias.

I did not even realize for a while the new version can be put on a timer. :mrgreen:
That alone makes it far superior and worth the upgrade IMO, never mind annoying noises.

Any calcium deposits on it?
Try submersing in vinegar overnight, non running, to see if that helps.

I had the same thing happen to one of my k4's. I took it out of my tank and I'm replacing it soon.

edit - I cleaned the pump and still the same sound.

They are so cheap , get some new ones .

I have my EVOs on timers but they sometimes rotate backwards (which they are not supposed to do). I can prove this because my macroalgae gets sucked into the front of the powerhead instead of being blown away.

Otherwise very happy with this cost-effective water mover.:biggrin: