If you are adding iodine once a week I'd sure consider adding a good and reliable test kit for iodine....it is relatively easy to over dose iodine and my understanding high concentrations can be lethal.
But...as for feeding the red shrooms...they really don't require much except decent lighting(mine don't do well in high light) and stable water chemistry.Mine have never responded to any foods added....possibly DT's...but I'm not sure if DT's is a food source for them or not.:thinking: