Having the same problem myself just now, been the last few weeks.
Hit me all of a sudden, still trying to shift it but getting there slowly.
As already mentioned I've cut back on lighting and doing water changes every few days, deffo helping.
Hey everyone,
Im new to the forums, just thought Id say hi.
I have kept tropical tanks for 10 years (on and off). Ive been running my current setup for 2.5 years.