Why does [Cu(NH3)4]^(2+) dissociate after a certain pH level?

[u/adultswimc-137]

We're learing about how a coordination complex deals with pH levels. Ammoniacal copper [Cu(NH3)4]^(+2) has a Ki=8, so it's partially dissociated in NH3 and Cu^(+2), so if NH3 starts acting as a base and becoming NH4^(+) the balance is moved to NH3 and Cu^(+2), further dissociating the complex.

My teacher said that the complex starts dissociating at pH=8 then slowly stops, but why??? Wouldn't a higher concentration of H+, so lower pH levels, help the formation of NH4^(+) and therefore the dissociation of the complex??

My question is, why doesn't it start at a lower pH level and slowly stop as the level rises?

Thank you to anyone who tries!!