Fluval FX5 noise after cleaning

[Rokuzachi]

So I cleaned my FX5 for the first time today because it seemed to be cavitating. It was incredibly quiet during its first month of service including while it was spewing bubbles these last two days.

Now, after the water change, it's got a decent buzz to it even after purging all the air. I'd say it's about on the level of an AC110, maybe a little louder. Should I be concerned and have a backup impeller assembly on standby, given that the thing was almost silent prior to the cleaning?

I was thinking that maybe some particulate got into the impeller (the intake is about 12" from the bottom of a tank with a sand substrate). I've read that other people have had problems with noise when running a polishing pad (which I have one of in the canister at the moment). I've tried dialing down the in/out valves and it does nothing.

This concern comes at a horrible time with the holidays and travel coming up. Ugh.

Any insight is greatly appreciated.

 

[Togliat]

I have an FX5.
Intake is about 4" from sand substrate. No sand issues.
However, during priming from my bucket, I accidentally got a tiny bit of sand in mine but no immediate problems.
Been running about the same amount of time as yours, maybe a couple weeks longer.
Noticed low flow, serviced the filters baskets, found excessive BB in my mechanical filter.
It was the cut-to-fit filter material and the water could no longer get by as the filter was cruddy with goop.
Flow returned to normal after I tore up the round filter.
No issue with noises, but did get the cavitation you mentioned.

Try playing with your filter materials a bit to see if that has any effect.

Is the flow rate as strong as when new?

 

[Rokuzachi]

Thanks for the reply.

The flow rate is still very high. It was noticeably lower before the cleaning - the coarse and fine pads I had used were literally a wad of slime. I think I may try removing the fine pad tomorrow and replacing it with more coarse.

My 405 regularly has fine sediment in it from my substrate and it's been running like a silent champ for over 8 months now, so I was just concerned when suddenly the silent FX5 started buzzing like an Aquaclear the instant I plugged it back in. If it gets any worse, I'm going to break it down and take a look at the pump.