I have two domains named, for example, AA.com and BB.com. BB.com is the main site. AA.com ranked at #3 for a KW. BB.com ranked nowhere for this KW. I 301 redirected AA.com to BB.com. AA.com received its ranking and stood at #3. Over a period of a year, the rank has fallen and is now at #10. I want to do SEO and get the rank back up. Where do I do SEO on? On AA.com (original domain) or BB.com?