new tank setup KH is high, won't have PH swing issue.

test kit are expensive, just helping him to save $, lfs will ask you to buy everything.

if NO3 is high meaning nitrobacter already there, is good sign. just do wc once a week.

ammonia spike because not fully cycle, over feed or dead fish. how to fix? also wc, test also meaningless, just get more salt.

if he plan to do reef, after few mths , need KH test kit.
cal, mag, stron etc test kit are for hardcore.

if have budget go buy bit of rowa phos and active carbon.

cooling part, least need a termometer to monitor before can decide.