• Complete and concentrated conditioner for both fresh and saltwater
  • Removes chlorine, chloramine
  • Detoxifies ammonia, nitrite, and nitrate
  • 5X more concentrated than competing products


Prime® is the complete and concentrated conditioner for both fresh and saltwater. Prime® removes chlorine, chloramine and detoxifies ammonia. Prime® converts ammonia into a safe, non-toxic form that is readily removed by the tank’s biofilter. Prime® may be used during tank cycling to alleviate ammonia/nitrite toxicity. Prime® detoxifies nitrite and nitrate, allowing the biofilter to more efficiently remove them. It will also detoxify any heavy metals found in the tap water at typical concentration levels. Prime® is non-acidic and will not impact pH. Prime® will not overactivate skimmers. Use at start-up and whenever adding or replacing water.

When transporting or quarantining fish, use Seachem StressGuard™. When adding new fish, use Stability®. Both are ideal for use with Prime®.

Nearly all companies manufacture a product that removes chlorine. None of those, however, can compare in quality, concentration, or effectiveness to Seachem’s flagship product: Prime®. Prime® is the second most concentrated dechlorinator on the market after our own aquavitro alpha™. A single 100 mL bottle will treat 1000 US gallons of tap water. Prime® will remove both chlorine and chloramines from municipal water supplies.

Prime® also contains a binder which renders ammonia, nitrite, and nitrate non-toxic. It is very important to understand how those two functions work together. All dechlorinators operate through a chemical process known as reduction. In this process, toxic dissolved chlorine gas (Cl2) is converted into non-toxic chloride ions (Cl-). The reduction process also breaks the bonds between chlorine and nitrogen atoms in the chloramine molecule (NH2Cl), freeing the chlorine atoms and replacing them with hydrogen (H) to create ammonia (NH3).

Typically, dechlorinators stop there, leaving an aquarium full of toxic ammonia! Seachem takes the necessary next step by including an ammonia binder to detoxify the ammonia produced in the reduction process.

Be very careful when purchasing water conditioners. If your municipality includes chloramines in the water supplies, a standard sodium thiosulfate dechlorinator is not enough. Prime® promotes the natural production and restoration of the slime coat rather than relying on artificial or non-native slime compounds. A further bonus for the reef hobbyist—Prime® will not overactivate protein skimmers.


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.


50 mL, 100 mL, 250 mL, 500 mL, 1 L, 2 L, 4 L

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

A: 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).

A: 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.

A: 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.

I wish we had some more "concrete" explanation, but the end result is the same, it does actually detoxify nitrite and nitrate. This was unexpected chemically and thus initially we were not even aware of this, however we received numerous reports from customers stating that when they overdosed with Prime they were able to reduce or eliminate the high death rates they experienced when their nitrite and nitrate levels were high. We have received enough reports to date to ensure that this is no fluke and is in fact a verifiable function of the product.

A: Prime can be dosed every 24-48 hours.

A: 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.

A: 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.

A: If your ammonia or nitrite levels are above 2 ppm, you can safely use up to 5 x the recommended amount.

A: No, as long as Prime has been stored properly, it will last indefinitely.

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0434 Prime 50 mL
0435 Prime 100 mL
0436 Prime 250 mL
0433 Prime 500 mL
0437 Prime 1 L
0438 Prime 2 L
0439 Prime 4 L