I once saw a post, where on the Flop we should have a 2:1 ratio in favour of bluffs, on the Turn 1:1 and on the River 1:2 in favour of value hands. In another post I saw that the combos we should bluff with change when we use difference pot sizing.
So why should i have on the Turn for example a ration of 1:1 although I bet for example 75% of the pot. (when I bet 75% of the pot I'm laying to my opponent 3:7 pot odds --> so that would mean 3 bluff combos for every 7 value hands -->43% bluff combos ). I don't get why I should bet on the Turn with a 1:1 ratio.

Can anybody help me?
Thanks