I set up a 540 4 months ago, new sand, new DW, same as you. Purigen took out the Tannins and I didn't boil it at all. The the water was cloudy, not bad but irritating. I just left it alone, 3 months later it's getting crisp and clear now.
My theory is new sand clouds water slightly no matter how much you rinse it. Just take time to filter it all out.
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