Ok I have never in 30 years with this tank had this issue. Started with a sever hair algae outbreak!!! For the last six months hair algae it dies I clean tank change 20% water changes every three weeks or so… hair looks like brown diatom everywhere but grows like hair??? I removed and cleaned the rock, red slime outbreaks twice treated it this is now the third time. I have snails, crabs, cucumber, urchin, fish all eating some but snails and crabs are dying off urchin gone. Cucumber hanging in there. Water is good nothing is high
