You could put something like this on the outlets of the Delta 2 instead of getting Inkbird and waiting for the temperature to drop.
https://www.amazon.com/Failure-Adjustable-Indicator-Refrigerator-Aquarium/dp/B0CZMGL2D2/?th=1
Hydroids
I tossed the monti, rock, and frag racks that were infested. It’s been almost 6 months and I haven’t seen any sign of them. Maybe I got lucky and had hydroids that didn’t produce free swimming medusa - fingers crossed.
Ostreopsis Dinos
I bottomed out my phosphate and ended up with...