I have a Hayward Star-Clear Plus Cartridge filter (C1200). I clean the filter every 2-3 weeks by taking it out and hosing it down to get all the dirt and gunk out. But how do you know when the filter needs to be replaced and not just cleaned? Also, someone told me i need to lubricate the O-Rings and gaskets. Is that true? What should I use to lube them? or should I just replace the O-Rings periodically?