How can i prevent the bad breath from acid reflux and keep breath fresh all day and night?

Make sure: You are being properly treated for your reflux. In addition make sure you exercise good oral hygiene (mechanical toothbrush, waterpik type of device) and are also brushing your tongue. You might also try a mouthrinse system called smart mouth. I have some patients that use it and have positive results. Also make sure you see your dentist for regular cleanings and checkups.

Sleep on empty tummy: Try to eat your meal 2 hr before bedtime to allow for stomach emptying thus reducing the amount of digesting acid in your stomach. Moreover, avoid fatty food which cause slower emptying of stomach.