Seachem Prime is a highly concentrated aquarium water conditioner for freshwater, saltwater and planted aquariums. Use Prime whenever adding tap water, setting up a new aquarium or dealing with an ammonia or nitrite emergency.
Prime removes chlorine and chloramine and detoxifies ammonia, nitrite and nitrate, helping protect fish while your biological filter processes these compounds.
Why Use Seachem Prime?
- Makes tap water safe for aquarium use
- Removes chlorine and chloramine
- Detoxifies ammonia, nitrite and nitrate
- Suitable for freshwater and saltwater aquariums
- Will not affect aquarium pH
- Can be used during aquarium cycling
- Highly concentrated and economical
At Simply Fish, Prime is one of the first products we recommend for new and established aquariums. It is simple to use, extremely concentrated and provides additional protection beyond a basic dechlorinator.
Seachem Prime Dosage
Use 1 mL of Seachem Prime for every 40 litres of new water, or 5 mL for every 200 litres.
When treating replacement water in a bucket, calculate the dose based on the amount of new water being added.
When adding Prime directly to the aquarium while refilling, calculate the dose based on the total aquarium volume.
Approximate Treatment Capacity
| Bottle Size |
Treats Up To |
| 100 mL |
4,000 litres |
| 250 mL |
10,000 litres |
| 325 mL |
13,000 litres |
| 500 mL |
20,000 litres |
| 2 L |
80,000 litres |
Always follow the directions on the product label. In certain emergencies, Seachem permits higher doses, but the underlying cause of elevated ammonia or nitrite must still be corrected.
When Should You Use Prime?
Use Seachem Prime:
- During every aquarium water change
- When filling a new aquarium
- When adding tap water directly to an aquarium
- During fish-in cycling
- When ammonia or nitrite is detected
- When transporting aquarium water or livestock
- After an accidental exposure to untreated tap water
Prime temporarily detoxifies ammonia, nitrite and nitrate rather than physically removing them. Your biological filter and water-change routine must still process or remove the underlying waste.
Which Size Should You Choose?
100 mL: Best for nano aquariums and smaller tanks.
250 mL or 325 mL: A good general-purpose size for most home aquariums.
500 mL: Better value for larger aquariums, multiple tanks or frequent water changes.
2 L: Best for fish rooms, large systems and commercial aquarium maintenance.
Frequently Asked Questions
Why does Seachem Prime smell like sulphur?
Prime naturally has a strong sulphur-like smell. This is normal and does not mean the product has expired.
Are black particles in the bottle normal?
Small black specks can occasionally appear in Prime and are considered normal by Seachem.
Does Prime remove ammonia from the aquarium?
Prime does not physically remove ammonia. It binds or detoxifies it temporarily, allowing the aquarium’s biological filter time to process it.
How long does Prime detoxify ammonia?
Seachem states that Prime can bind ammonia, nitrite and nitrate for up to approximately 48 hours. Prime is an emergency safety measure, not a replacement for proper biological filtration and water changes.
Can Prime be used in saltwater aquariums?
Yes. Seachem Prime is suitable for both freshwater and saltwater aquariums.
Does Seachem Prime expire?
When stored correctly, Seachem states that Prime has an indefinite shelf life.
