maybe put the old filter back and run in conjunction with new filter until it’s established-
test water with API - grab some prime to make water safe (have to dose every day)
post water param
I should have clarified that better- I no longer have the original filter (it died), so I'd be buying a new version of the original.
But thank you- I did what you said (and two other steps), and he's back to normal now.
Thank you so much for responding!!