Maybe it would be a good idea to check the free chlorine level in the pool water itself? That way, if there is no chlorine in the water, then you'll know that your chlorinator is not working.
While you're checking the levels, take a look at the CYA, or stabilizer, level too. It'll help determine just how high your FC (free chlorine) level needs to be.
What do you use to test your water? Could you post your results?