поддерживать баланс(between something and something: We try to be good web neighbors by striking a balance between protecting you from bad ads and depriving responsible sites of the revenue they need to provide the content you love.4uzhoj)
соблюдать баланс(For this reason, a balance has to be struck between the necessary measures on the one hand and the ability of transport system to operate efficiently on the other handIrina Verbitskaya)
