The likely cause is nute temp is too warm. Often the case when the pump is inside the root chamber. Solution go to an outboard pump with a drain back. This also simplifies cleaning and changing nutes. If need be you can ut frozen jugs of ice into the rez to cool the tmep to ~ 65-70*s
If possible use a light spray as from a shower wand to remove the slime. This works much faster than running Physan. Then spray or soak the roots in 3% H202 to disinfect.
Also check pH and ppms. During flower they will significantly increase within 12 hours, creating an unhealthy environment.
After doing these things, I never have slime anymore
