You can actually use any of the filters on the following page for your system:
http://www.waterfilters.net/culligan/wholehouse/replacement_filters/Wholehouse-10-Inch-Filters.htm
There are a lot of options! The best one depends on what you want to
reduce out of your water supply.
The 1 micron sediment filter is located here. This one will reduce the
most sediment.
http://www.waterfilters.net/Pentek/wholehouse/Sediment_Filters/P1.htm
I would get the spun polypropylene P1 over the pleated type of 1
micron filter. It is more durable.
There are also carbon filters that reduce more than just sediment.
They are more expensive than just plain sediment filters. This filter
reduces sediment down to 0.5 microns, reduces chlorine, and reduces
lead:
http://www.waterfilters.net/Pentek/wholehouse/Carbon_Filters/CBR2-10.htm
You should ONLY use this filter if you have a dedicated drinking
faucet for your housing. The flow rate is too slow for a regular
faucet.
If you don't have a dedicated drinking faucet and you want to reduce
chlorine in addition to sediment, you can use this filter:
http://www.waterfilters.net/Pentek/wholehouse/Carbon_Filters/EPM-10.htm
This page lists replacement parts you may need as well for your
housing including o-ring, o-ring lubricant, wrench:
http://www.waterfilters.net/American-Plumber-W34-PR-Water-Filter-Housing_p_111-1654.html
Thank you,
WaterFilters.NET