10 x 750 ml = 7.5 litres.
Cambridge recommend 2.25 litres to 4 litres minimum a day for the average person doing average things.
If you're extra tall, extra heavy, have a very energetic day or it's very hot weather, you need more rather than less.
If the opposite is true of you, then you probably need the smaller amount.
However much you have, drink it regularly throughout the day, rather than glugging it, which will go straight through you, causing endless trips to the loo and do you very little good!
I'm 5'10", and drink about 3 litres of fizzy water a day with food, or 6 litres on sole source.
I think 7.5 litres is probably (a better word would be possibly!) too much.