ATO isn’t really needed. I manually topped off my tanks for years. At the 24 min mark Wincey talks about her ATO.
Yes an a.t.o in not really neccessary but using that same argument you could say test are not really necessary. Again no argument just in opinion... so either of us is right just wanted to a$$ my opinion.
Yes test kits are great to figure out problems and to get ahead of them... but if you are not dosing and see no problem in your tank and corals are growing and you are doing consistent water changes you can absoulty run a reef tank without testing.
Same with an a.t.o you can absoulty run a reef tank without one just the thing with the a.t.o after purchase you will wonder why it took me so long to buy this sure you will not be saying that with test.
I dont know I.M.O buy the test as you need them... that's what I did now I have red sea, a.t.i hannah checkers, t.d.s, p.h, refroctometer, so on and so on lol didn't buy all at once...