I pulled some water out of my fish tank today to use for seed starting and it looked like the picture above. I have used chelated iron before (the good kind recommended by vlad and silvia) and the fish seem to otherwise be very happy and healthy.
I'm really just concerned as to whether this is normal for fish tank water and, if not, are there long term effects of water looking like this.
Not seen in the picture is that the water remains clear but has the color of a cup of tea. All other parameters are good. PH-7.0-7.2, Nitrites-0, nitrates-20-30, temp-approx 28 C. Oh, and the fish are white nile tilapia.