First, you need to get a Mg test kit, preferably Salifert or Elos.
You need to increase Mg level to 1600-1700 and keep at this level for a minimum of 4 wks. Once you start seeing die off, you can siphon it up, but do not manually remove it, doing so will release spores causing more byropsis to multiple..
So people have noticed some issues with SPS and inverts, but when I did it, I did not notice anything. I dont keep SPS, mainly LPS and was OK.
This method of treatment is NOT a panacea..It WILL take time and can't be rushed, so your patient cap needs to be put on.