i killed them again. did a multiple treatment approach similar to a cancer chemotherapy
what i did: silicarbon to remove silicates, lights out for 2 days and ramp them for 2 hours more every day, take out the sump from the circulation and install an intank skimmer, bring KH to 9, and dose a chemical from my lfs. after a week they were completely gone. now i will have to see if they come back, but last time i did this it killed them for over 2 years.
if anyone is willing to analyze the chemical i could send a sample, as the packaging does not state whats in there. i suspect some kind of antibiotic or herbizide. nothing else suffered, neither my sps, lps nor my rbta.
greetings martin