Is there a way to make iron oxcide soluble

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I have an iron oxcide slurry mixed in with other water going through sand. My problem is since Iron oxcide isn’t soluble it eventually builds up on the top of the sand preventing any water from going through. So I’m wondering if there’s an easy way to make the slurry soluble again before it mixes with more water and ultimately plugs up the sand.
Pic related is sand with the aforementioned problem.