Out of Stock No Longer Available Seachem Prime Marine & Freshwater Conditioner, slide 1 of 1

Seachem Prime Marine & Freshwater Conditioner

  • Price:

    $4.31 FREE Shipping over $49

No Longer Available This item may be discontinued. We're not sure when it will be available again.

Seachem Prime Marine & Freshwater Conditioner is a complete, concentrated conditioner for both marine and freshwater aquariums. It effectively removes chlorine and chloramine, and detoxifies ammonia, converting it into a safe, non-toxic form that is readily removed by the tank’s biofilter. Prime detoxifies nitrite and nitrate, allowing the biofilter to more efficiently remove them. It will also detoxify heavy metals found in tap water. It is non-acidic and will not impact pH. Use at startup and whenever adding or replacing water.

Key Benefits
  • Complete and concentrated conditioner for both fresh and saltwater. Prime removes chlorine, chloramine and detoxifies ammonia.
  • Converts ammonia into a safe, non-toxic form that is readily removed by the tank’s biofilter. 
  • Easily removes chlorine and chloramine, and is non-acidic so it won't impact pH level.
  • Also detoxifies any heavy metals found in tap water.

HAZARDS TO HUMANS: Contains complexed hydrosulfite salts. Aquarium use only. Keep away from children.

Special Note

  • 3.4-oz bottle treats up to 1000 gallons.
  • 8.5-oz bottle treats up to 2500 gallons.
  • 17-oz bottle treats up to 5000 gallons.
  • 67.6-oz bottle treats up to 20,000 gallons.

See all items by Seachem

  • Item Number
  • Aquarium Type
    Freshwater, Saltwater
  • Fish Type
    Tropical Freshwater, Marine Fish

Use 1 capful (5 mL) for each 200 L (50 US gallons) of new water. For smaller volumes, please note each cap thread is approximately 1 mL. May be added to aquarium directly, but better if added to new water first. If adding directly to aquarium, base dose on aquarium volume. Sulfur odor is normal. For exceptionally high chloramine concentrations, a double dose may be used safely. To detoxify nitrite in an emergency, up to 5 times normal dose may be used. If temperature is > 30 °C (86 °F) and chlorine or ammonia levels are low, use a half dose.


I think that my Prime might be old because it smells like it went bad.

Prime has a very distinct odor that is similar to sulfur which is completely normal. Also, the presence of small black specks is normal.

I am using Prime to control ammonia but my test kit says it is not doing anything, in fact it looks like it added ammonia! What is going on?

A Nessler based kit will not read ammonia properly if you are using Prime®... it will look "off scale", sort of a muddy brown (incidentally a Nessler kit will not work with any other products similar to Prime). A salicylate based kit can be used, but with caution. Under the conditions of a salicylate kit the ammonia-Prime complex will be broken down eventually giving a false reading of ammonia (same as with other products like Prime®), so the key with a salicylate kit is to take the reading right away. However, the best solution ;-) is to use our MultiTest Ammonia kit; it uses a gas exchange sensor system which is not affected by the presence of Prime® or other similar products. It also has the added advantage that it can detect the more dangerous free ammonia and distinguish it from total ammonia (total ammonia is both free ammonia and non-toxic ionized forms of ammonia).

I tested my tap water after using Prime and came up with an ammonia reading. Is this because of chloramine? Could you explain how this works in removing chloramine?

Prime works by removing chlorine from the water and then binds with ammonia until it can be consumed by your biological filtration (chloramine minus chlorine = ammonia). The bond is not reversible and ammonia is still available for your bacteria to consume. Prime will not halt your cycling process.I am going to assume that you were using a liquid based reagent test kit (Nessler based, silica). Any type of reducing agent or ammonia binder (dechlorinators, etc) will give you a false positive. You can avoid this by using our MultiTest Ammonia kit (not affected by reducing agents) or you can wait to test, Prime dissipates from your system within 24 hours.

How does Prime make a difference in reducing nitrates?

The detoxification of nitrite and nitrate by Prime (when used at elevated levels) is not well understood from a mechanistic standpoint. The most likely explanation is that the nitrite and nitrate is removed in a manner similar to the way ammonia is removed; i.e. it is bound and held in a inert state until such time that bacteria in the biological filter are able to take a hold of it, break it apart and use it. Two other possible scenarios are reduction to nitrogen (N2) gas or conversion into a benign organic nitrogen compound.

If Prime is removing ammonia from the system, won’t that starve the beneficial bacteria?

Prime does not remove ammonia, nitrite, or nitrate from the system. It simply binds with those compounds making them harmless to the inhabitants and still bioavailable to the beneficial bacteria.

How long does Prime stay bound to the ammonia, nitrite, and nitrates?

Prime will bind up those compounds for up to 48 hours. If they are still present after that time frame, they are released back into the water, unless Prime is re-dosed accordingly. Also, if your ammonia or nitrite levels are increasing within a 24-hour period, Prime can be re-dosed every 24 hours.

Rating: 4.8 of 5 stars 90 Reviews 90 Reviews 4.9 out of 5 Stars

Filter reviews by star rating

96% Recommend

96% of reviewersrecommend this product

Rating: 4.8 of 5 stars 4.9 / 5

You've Already Reviewed This Item