Nope never, sometimes it gets warmed up, sometimes its cold on purpose in summer. Sometimes its really cold in winter.o you match the water you are changing in? -
None if that matters. What matters is bad water goes out and fresh in.
I checked your lights probably from your post, you have 3w led chips, and they will cook coral just as easy as any other led light will. Your growth issues could be over intensity.
This whole new keep nitrates and phosphates higher then old school, is biting a lot of people in the butt. It bad advise, and lowers your safety margin between stability and crashing