That was amusing. The $30 filter either has a wider pass band or less attenuation than the floppy disk. You can layer the filter or just whack a single floppy disk layer on. The camera lenses have a finite number of filter swaps before their focus has to be redone.

The guy mentioned the floppy disk was merely attenuating the entire spectrum instead of selecting for IR, while the $30 filter was selecting for IR. If that was true, a bright white LED would show through the floppy disk, but it doesn't. Only a red LED shows.

Also, looking through the floppy & the $30 filter with the naked eye shows the same pass band, with slightly more light passed through the $30 filter.