It almost looks like the rust on my apple tree outside lol.

Bigsby has it right I think. Are you measuring the pH of your water? A calcium or magnesium deficiency can cause textured spotting; look into calmag as a quick fix. There are other methods of introducing calcium and magnesium (egg shell powder, etc) but those methods never seem to work for me. pH fluctuation can cause a lock out of calcium, so i would invest in a ph tester of some sort. good luck!