I wanted to buy an extra filter for my Caldera Palatino so that I have a spare while I'm cleaning the other filter. My Palatino came stock with a standard 65 sq feet paper filter, watkins pn 71827 (stamped 31114 on bottom) measuring 10.5"x8.5" with 3" inner diameter. Would the Hot Spring Tri-x filter work in this tub? It appears that the inner and outer diameter is smaller on the tri-x compared to the 71827 so I assume that it wouldn't.