Yeah, you can't top off your nutes and here's why: You start the week with 800 ppm and 3 days later you are down to 700 ppm. What nutrients were depleted and what weren't? So you top off another 100 ppm of all the nutes and some nutes are now overstrong and others are still under.

I don't know about a scrub down every week. But full water change and nutes weekly is average.

Rez temp is good under 80 degrees.