Help me please with my Blau dc pump.

My dc pump has been running now for nearly 18 months, and today it has started "micro stopping" well it's not quite stopping just a stutter, slows down a slight bit, and then comes back up to speed.

It's doing it about every 10 seconds or so.

It's cleaned regularly and everything is plugged in firmly.

Any ideas on what wrong and how it can be fixed?

I would sudjest the controller is at fault , try seahorse i am sure they would have a controller you could try , always found them super helpful

Well I took it apart again, cleaned it again still the same.
So out of frustration I shook it, put it back in the water, perfect! Has missed a beat again!
So I don't know what it was but it's running ok again now.
So will wait and see what happens.
Thanks for the thoughts.

Its strange this , happens to me sometimes being a mercanic i take something apart cant find anything wrong put it back together and presto it works perfectly . Lets hope your problem is solved