I've measured it. My 15lb 1.5yr old sulcata drinks between 6 and 9oz of fresh water from the dish every morning. About 1/2 of a 16oz bottle.Sulcata cannot process sugars.
It really is just that simple.
It shouldn't be....And most importantly doesn't need to be fed.
One generation isn't enough to change a tortoises physiology or digestion system.
Sulcata should have access to water pools. They drink from them. Soak in them. And most want to stay in them all day long.
That water content from foods concept is decades old. It was wrong back then. Still is and it's unsettling to hear it bought up again after all of this time.
That amount of water is totally inadequate.