Thanks grimsteph, I just went online and found the DTPA chelated iron from Allied Aqua and placed my order for some. Dr. Nate Storey also talked about it in his Iron Video, said that they used that type...but recommended the EDDHA chelated iron. Even though it was harder to find and more expensive, because it would work in systems with a pH level up to 9ppm.
I will be doing water exchanges to remove my very red AP water to my organic garden, replacing it with my rain water. Then start adding the DTPA...it will be nice to see my fish again.