Nitrates are a lot less, but i've never went over a 30% water change lol, doing a 50% i start to panic ...
Especially my 92 gallon tank in the livingroom (My Oscar Tank) i had my missus out measuring half the tank so i wouldnt go over ....
Even then it seems to much, altho my fish dont seem to mind tbh, and i hear folk do 75% changes :-?
Brucey