I am using a cathedral as a post effect after my mixer since I am playing multiple instruments at nonce and want the option to have its amazing reverb with each instrument. I am getting huge feedback at normal volumes and loud volumes I can’t seem to avoid it unless I reduce the effect to a very small amount. Does anyone have any suggestions for keeping the verb effect without introducing overwhelming feedback?

The flow I have is instruments, mixer, cathedral, looper, amp or pa.

Thanks in advance,
-joel