I ordered some iron chelate because I'm thinking not having any is stunting the growth

I was reading more about chicken/duck poop and how they use it as the main fertilizer for azolla, it contains iron. I realized that the fertilizer I've been using contains no iron, so a tiny amount of this should make the growth much faster. The azolla right now is competing for the scarce iron in the tap water which is not ideal. Now that the small amount of iron has been absorbed from the water, the growth is stagnating again.