Hi there, I too have an LA Spa, I have found that a paper filter works just fine in my concord tub. Here is the number of filter that I have been using FC-0315 by Filbur also replaces the 6CH-47 it is 6"x9" w/1-1/2 theards. Hope this helps.
Just wondered why you went to the paper filter? Did you find that LA Spas filters did not last long? How long do the paper filters last and how much do they cost?