Return pump microbubbles

[potsy webber]

I have a Solana and am having a problem with microbubbles entering the tank via the return pump. I don't know if the bubbles are coming from the stock skimmer in chamber 1, through chamber 2, which is polyester fiber followed by a 4"X12" bag of Matrix, carbon and Chemipure, followed by chamber 3 with the return pump. Or, if the return pump is the origination point.

 

I know microbubbles aren't bad for the tank, but they are kind of annoying. Any tips on how to make them stop?

 

Also, from when I added sand to the tank, some of it settled in the chamber with the return pump. Is it OK the leave it there? Or, the next time I do a H2O change, should I siphon it out?

 

thanks