You MAY be one of the few people for whom phosphate treatment is appropriate--since it looks like somebody put fertilizer in your pool!

Search the entire forum for references, especially posts by PoolDoc-the forum's owner. At this point, his is the only advice I would trust on this--whether or not you need to act, if so what to add, and what to expect when you do.

Until then run your FC up to 15ppm and keep it there until it holds without dropping precipitously. I KNOW that this is not the best thing to do with metal stains, but you MUST make sure algae doesn't start growing. You can try ascorbic acid on the stains.

If this is advice isn't correct, PoolDoc or one of the other moderators or our most experienced members may correct me, but you should be OK doing this.