If the bubbles are coming out from the rainbar, then like another reefer mentioned, likely air is being sucked into your canister or piping, creating micro bubbles in your outlet stream.
You would have to investigate where the leak is and fix it.
If it is foaming caused by normal water agitation, then likely your protein level is currently too high. Skimmer would solve it.
As for the smell, it should go away after this cycle is finish and major water change done.
But if you really really cannot bear with it, use Activated Carbon to get rid of it.
Good luck:)