My new Hayward cartridge filters have clogged after about 2 months of service. I water washed them thoroughly after they developed the recommended 10 psi pressure drop.

I'm at the point now of very little flow thru them after water washing. I've never had this problem before. The old cartridges lasted 4 yrs. These are shot after 2 months.

My water chemistry is fine per the Leslie analysis. The water is cold with no algae evident on the pool walls or steps.

Is there a better washing method? The only difference I can see between the old and new cartridges is the new ones have "2 micron" stamped onto the end cap. Are there different micron ratings for cartridges?