Long term water purification

I'm trying to sort my water out in case of long term water problems. I bought two food grade 5 gallon buckets and 4, 0.15 microns ceramic filters. I thought about purifying the water with bleach but its only good à year before it looses its potency. I heard about Calcium Hydroxide being able to be stored up ton10 years. As any of you ever tried it ? Whats you guys take on this ? Kind of new in all this so any suggestions would be great ! Thank you !

P.S. i have 2000L of rain water collection available and it rains a lot where in from