How much nori is too much?

[Ruth]

Naesco where do you get the discs from. I feed a half sheet in the morning and another half in the evening. On the weekends when I am home I will quite often feed another half sheet around 2pm. My fish go crazy and it is all gone in about 2 minutes. The rest of the day is spent picking any algea that has the nerve to show itself off rocks, glass etc. I assume they are getting something but there is no algea visible in that tank.