I am not the most experienced grower out there but I try to answer when I can cause I notice so many post get little response even mine.
I guess I have always just gone simple, 3 part hydro nutes, some ph down/up, some quality
cal-mag, some ml graduated cylinders, some pipettes, an H&M ph meter and an H&M ppm meter. I did just buy a brix meter but that to me is an extra.
If you really love growing after a while you might want to invest in a chiller (~$275 on amazon). It is easier to use the ice method if you eventually build a simple recirculating system.
Dee