copephod is gone

I've been observe lately in my sump there is no copephod or amphipods again, its start from almost all caulerpa being withered in the sump.
Anyone know why ?? I check PH KH is still normal.

There was many copephod or amphipods before caulerpa start withered.
now copephod or amphipods dan caulerpa is gone :confused::confused::confused:

is that relate with bacteria?

Pods eat algae, so with less caulerpa there is less food for pods.