I use to have these cover every rocks in the tanl when my N03 go up from 0.03 to 15 ppm.
After I run biopellet and volda for one month and NO3 drop back to almost zero these star also thin
out
Last 3 weeks I was too busy to look after my tank I can now see some of them coming back.
Need to check my NO3 again to see if NO3 is the root of this problem