How many bio balls for a 200 gallon aquaponics system?

For a 200-gallon aquaponics system, we would recommend 1 bag of our 300-pack of bio balls. There are variables that affect how heavy a bio-load is in an aquaponic system including: how many fish, their size, how often they are fed, and so on. The only way to know if you have enough bio balls is to test your water for ammonia or nitrites. If you detect ammonia or nitrite levels in your pond water (not caused by overfeeding or a dead fish) add more bio balls.