Basket Filters
If your rainwater collection tank has a 16" tank lid (most tanks do), and you want to continue to use the lids, you would choose from the first 2 options:
1) 16" SS Filter Basket w/ Lifting Handle. This one works best when a screw-on lid is in use, because it's easiest to remove from the tank for emptying/cleaning. Plus, it will essentially last forever.
2) 16" Tank Basket Filter w/ Nylon Mesh Screen. This one serves the same purpose as the SS version above, but it's less expensive. The issue with these is that they can be more difficult to remove for emptying/cleaning from the screw-on lid's mounting ring once they are installed if you seat/recess them down far enough to be able to screw the lid on properly.
3) If you prefer to remove the screw-on lids from the tanks and still want to prevent sunlight penetration, use the 16" High Flow Leaf Basket Filter w/ Light Guard. It allows the rainwater to pass through while keeping the sunlight out, but they are not to be used w/ the existing screw-on lids. They replace them. Be sure to use a tek screw to secure the filter basket with the light guard so that they blow off of the tank when it's windy.