Intex saltwater system

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.

Most saltwater systems supply enough chlorine ONLY if everything else is OK.

Green goo on filters is usually algae, which can eat chlorine for breakfast, lunch and supper, as well as midnight snacks. Do three things:

#1 - buy a cheap OTO / phenol red testkit, and test your chlorine in the evening AFTER you dose and in the morning no more than 2 hours after sunrise.
#2 - add 1/2 gallons of plain 6% bleach to your pool in the evening -- test 1 hour later.
#3 - take your pool water to a dealer, and have them test your pool for stabilizer. Buy enough stabilizer to raise your level to at least 50 ppm on a 5,000 gallon pool.

In the future, run your salt system, but boost with bleach any time it starts to get low.

Ben