I am 4 weeks into a new 15' X 48" metal frame intex pool using the included filter pump and an intex saltwater chlorinator. I've followed all the directions regarding the amount of salt to start with, recommended time settings, and all that. After 4 weeks of use the pool water seems clear as advertised however everytime I check the chlorine level, it alway indicates very low. I've run the boost cycle several times and have the system timer set to run about 4 hours longer than recommended with no increase in chlorine levels. The saltwater system has not given me any error messages and seems to be operating normally. Any suggestions? One note is that we are going through about 1to 2 filters every week and they always come out very dirty and greenish. The water source was city tap.