You can see a pic the setup I was running in this post:
After this post, I switched it to 25um bag → 1um bag → 1um cartridge. I wasn’t using an AC cartridge, the last stage was just for clarification since the bag is only somewhere between 65-80% efficient. What I can tell you from that though is that you’re likely to exhaust the the absorption capacity of the AC before you see a significant pressure drop across the last stage. The 30" pleated cartridge in my setup would easily last for at least 1200+ gallons. I wish I had run an AC cartridge and could give you an idea of it’s lifespan. If running cost is a major issue, it would be worth at least trying to find out the approximate lifespan and $/gal cost of a 30" cartridge filter vs. a lenticular cartridge, as lenticular cartridges can be as much as 10x as expensive as a 30". My guesstimation is that lenticular would be the way to go.