Calcium reactor circulation

I set up a coralife ca reactor last week on my 90 tank. I have heard bad reviews of the pump on this model and I'm wondering how well the water is circulating in the chamber. How do i tell if it is circulating?

 

You should have water coming out and the media should be tumbling a tint bit.

 

Now, tumbling is more for grinding and making sludge. Not what we are after

 

Thanks, don't use one so not sure.

 

I've got no tumbling. I see co2 bubbles coming up.