Is it okay for people on hemodialysis take blue/green algae?

No: Blue green algae also called cyanobacteria can produce toxins which can be harmful to health. There is paucity of data in this are and i would not recommend these to anyone at this time.

Ask nephrologist!: Suoplements are not regulated by the FDA, and can have many ingredients in them other than the one they are touting and different brands have different ingredients. Please always check with your nephrologist before taking any prescription or over the counter medication or any supplement. Take the bottle to his/her office and ask the staff to check with him and relay the answer. Good asking!