I have been getting a few diff types of blooms here lately. Feed the heck out of my tangs!! Started buying bulk nori about a year ago..last shipment was green and red mixed together, that was a month ago, now blooms everywhere. Only par that is a lil out of wack is po4 which is .5..need to change out GFO.. is it possible that red nori is leaching iodine into my tank? If so i need to get a test..How would you bring levels down? Thank's