Four Choices:

Bacteria Biosphere
Releases natural bacteria. Preps water, starts biofilters, bacteria booster, waste remover and ammonia detoxifier. Treats 1000 - 2500 gallons. Lasts 1 month.
Suggested Retail Price: $12.95
$10.99

Barley Biosphere
Beneficial natural bacteria barley extract and barley straw all in one. Treats 100-500 gallons. Lasts 1 month.
Suggested Retail Price: $12.95
$10.99

Dechlorinator Biosphere
Dechlorinates on contact. A must for Auto-Fills. Neutrailzes chloramines and protects from harmful chlorine. Treats 250 - 1000 gallons. Lasts 1 month.
Suggested Retail Price: $12.95
$10.99

Oxidizer Biosphere 
Helps keep and maintain debris-free waterfalls and rocks with minor buildup. Treats 100-500 gallons. Last 1 month.
Suggested Retail Price: $12.95
$10.99