Thank you for the info! I already happen to have some liquid carbon left over from a previous purchase so I might as well use it up but good to know it's not worth buying in future.
Incidentally I have been having trouble with black hair algae and cyano in one of my tanks, a grow out tank for two tiny delhezis. I read that cyano can be eradicted using erythromycin or Maracyn but fish medications are virtually impossible to get in Canad without a prescription nowadays. A blackout didn't help much either. I already do 50% water changes once a week to keep nitrates low so I thought perhaps boosting plant growth a bit would help them outcompete the algae.
Incidentally I have been having trouble with black hair algae and cyano in one of my tanks, a grow out tank for two tiny delhezis. I read that cyano can be eradicted using erythromycin or Maracyn but fish medications are virtually impossible to get in Canad without a prescription nowadays. A blackout didn't help much either. I already do 50% water changes once a week to keep nitrates low so I thought perhaps boosting plant growth a bit would help them outcompete the algae.