Pentek and American Plumber filters are both made by Pentair. The Pentek ECP5-BB is the same as the American Plumber W5CPHD.
ECP5-BB water filter and Pentek ECP5BB sediment filters 255490 for Big Blue whole house housings
The ECP5-BB has more dirt holding capacity than the CP5-BB so it should help for the lifespan of the filter.
You could also try a higher micron rating such as the ECP20-BB filter:
ECP20-BB water filters and Pentek ECP20BB replacement sediment filter 255491 for whole house water treatment housings
This is a 20 micron filter so it filters less sediment than the 5 micron filter. It won't fill up with sediment as fast. Your human hair is about 40 microns to give you an idea of how large a micron is. You can't see sediment as small as 5 micron or 20 micron so it's hard to know if your water has more sediment in it now than it did previously. The level of sediment will determine how often the filter needs to be changed. The level of sediment can vary over time in aquafir's. Here's some reading on aquafir's that explains how what is going at the surface can affect the quality of the water:
What is an Aquifer?
I'm not sure if you have a drinking water system but it is a good idea since aquifer's can have contaminated water as well. The contaminants can also vary over time depending on what surface run-off there is that gets down into the groundwater. This is a very good RO system and is easy to maintain:
PuROTwist 4000 Gold Series Reverse Osmosis System and PuROTwist 4000 Replacement Filters
Thank you,
WaterFilters.NET