We sell a lot of these filters for the Culligan AC-30 and the Culligan AC-15 RO systems. Your current filter may have a bump on the bottom depending on when it was made but the new compatible filter does not have the bump sticking out on the bottom; it should be flat. The bump was only there as an extra placeholder and is not needed. The Culligan compatible filters do look a little different than the Culligan branded filters but they work the same.
The AC-15 system and the filters for the 4 stages are located here:
http://www.waterfilters.net/culligan/reverse-osmosis/Culligan-AC15.htm
You will also need the RO membrane TFM-36-A. The RO membrane is what reduces dissolved solids such as nitrates, nitrites, barium, sodium so it is an important part of your system. It usually only needs to be replaced every 2 years but if you don't know when it was last replaced you should definitely replace it.
Here are the 4 stages in your RO system:
Stage 1:
This is the white filter without the netting. Your current filter may have
a bump on the bottom depending on when it was made but the new filter does
not have the bump sticking out on the bottom; it should be flat. Remove
the housing on your RO system, remove the old filter, and screw the new
filter in the housing.
Stage 2:
This will be the filter with the netting on the outside. Your current
filter may have a bump on the bottom depending on when it was made but the
new filter may/may not have the bump sticking out on the bottom. Either way it is okay. You will have to remove the housing on your RO system, remove the
old filter, and screw the new filter in the housing.
Stage 3:
This is the Membrane. This is the one blue membrane. You will have to
remove the housing on your RO system, remove the old membrane, and place
the new membrane in the housing. This is the one you didn't order. It removes the most dangerous contaminants from your water so I would recommend replacing it.
Stage 4: This is the short (6") white filter (post-filter). Your current
short postfilter may be either white or black. To use the short white
filter, you must remove the white/yellow plastic pieces in both ends of the
filter - pull on them to get them out. Then you insert your 3/8" line
directly into each end of the filter. The water goes all the way through
the filter. These are called quick connect fittings because you insert the
line into BOTH ends of the filter. The standard for the AC Series system
is the 3/8" line but we do have a 1/4" line filters as well if you have
1/4" line.
Thank you,
WaterFilters.NET