After realizing that the platypus soft bottle cannot be attached properly to the filter input (evernew bottles are perfect though), I still have not given up on attached my platypus bottle to the sawyer filter output.
To this end, I bought two aquasimple bottle caps (http://arrowheadequipment.webs.com/apps/webstore/products/show/1191146) and connected them with some food grade tubing and clamps. One cap makes a secure connection with the platypus bottle. The other cap screws down tightly on the filter output, however, there is a gap between the piece of the cap which attaches directly to the hose and the piece of the cap which screws down on the filter output. This gap causes leaks. I'm looking for a washer to take up the space between the two pieces. However, the size washer required appears to be non-standard (i.e., not available at Home Depot).
Has anyone solved this problem?
Thanks very much.