I have a Zodiac duoclear 200 swg. Normally on the chlorine output display there is one yellow and 2 green lights on. Now it is reading 2 green lights (no yellow light) and the red replace light is flashing. We had a new cartridge installed in May - could it need replacing already? When the pool company opened the pool, they turned the swg on when there was no salt in the pool (for a couple of days) could this have killed the cartridge early? If the red light is flashing, does this mean it is no longer sanitizing? (with test strips, my free chlorine is still reading around 3ppm) I have tried turning it off and on a couple of times, same result. Should I hit the Nature2refresh button? In the manual, it says to only hit this button when a new cartridge is installed. We have had a couple of electrical storms lately with power loss - maybe this affected the machine?