To find this cache you must complete the Solar Stroll [SS] section of the Marsh Mosh.
Whilst completing the Solar Stroll you will have collected all the bonus numbers you require to find this extra cache.
Please do not go to the publish co-ords... no caches will be found!
The cache can be found here:
N50 (F-K+J)(G+E).(K-J)(Z-Y)(F-H)
E000 (Z-F-K)(Y-K-J).(M-F)(Z-M-J)(Y-M)
For full description of the Marsh Mosh trails please see #1: http://coord.info/GC50KKF - The icons apply to all caches.