SeaChem Prime

Written by Kmuda. Posted in Dechlorinators


  • Complete conditioner for both marine and freshwater use
  • Safely condition water without a pH drop or overactivating protein skimmers
  • Provides essential ions and stimulates natural slime coat

No other aquarium water conditioning product is required to make tap water safe. Prime removes chlorine and chloramine (even in high chloramine levels), and detoxifies ammonia and nitrite. Provides essential ions and stimulates natural slime coat. Prime also detoxifies any heavy metals found in the tap water at typical concentration levels. When used during cycling, Prime enhances nitrate removal and does not cause a pH drop or overactivate protein skimmers. Great for setting up new aquariums, or when adding or changing water, or to remove nitrate. Use 1 ml for each 10 gallons of water. For freshwater or saltwater use. 100 ml treats 1,000 gallons; 250 ml treats 2,500 gallons; 500 ml treats 5,000 gallons; 2 liter treats 20,000 gallons.

Directions for Use: Use 1 capful (5 ml) for each 50 gallons of new water. For smaller doses, please note each cap thread is approximately 1 ml. This dose removes approximately 0.6 mg/L ammonia, 3 mg/L chloramine, or 4 mg/L chlorine.

May be added to aquarium directly, but better if added to new water first. If adding directly to aquarium, base the 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 > 86°F and chlorine or ammonia levels are low, use a half dose.

Principal Ingredients: Bisulfites and hydrosulfites, aqueous solution, buffered at pH 8, with ameliorating ingredients. Reducing agents.

Frequently Asked Questions regarding Prime:

Q. My Prime smells like it went bad, is it ok to use it?

A. Yes. While Prime has a very distinct odor that is similar to sulfur, this is completely normal and does not affect the performance of the product. The presence of small black specks is also normal.

Q: 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: 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.

Q: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?

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.

Q: How does Prime make a difference in reducing Nitrates?

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.

Seachem Prime Review

by Kmuda


There are many water conditioners on the market but in my view there are only two worth considering. SeaChem Prime is one of these two. Let's face it, all conditioners, for the most part, perform the same functions, some claim to do more than they can do, some claim to do things that really are not required and provide no real benefit, and some can be outright dangerous.

But when you get right down to it, there are only three things we need from a water conditioner.
The primary function we need from a water conditioner is to act as a dechlorinator. The second function we MAY require, is the ability of our conditioner to detoxify ammonia, but this is only necessary IF ammonia (or nitrite) is detected in our tap water. The remaining function that should exist in all water conditioners is the ability to bind heavy metals. If you don't think that "heavy metal" binding applies to you, think again. If your house is old, the pipes can be leaching everything from iron, to copper, to aluminum, to even arsenic. Have you heard about the "crumbling infrastructure" in America. Part of that infrastructure is your City's water system, which will also contain old pipes and equipment capable of leaching heavy metals. 

SeaChem Prime performs the three necesssary functions as well as any conditioner available to us, if not better. What makes SeaChem Prime my “complete conditioner” of choice, with “complete” meaning (to me) it also serves to detoxify ammonia, is that it is more economical than its competitors, achieved by being significantly more concentrated than competing products. While most conditioners require 1 teaspoon per 10 gallons, Prime is 1 teaspoon per 50 gallons. So while a bottle of SeaChem Prime may cost a couple of dollars more, you are actually getting 5x the product. Even if you only need a dechlorinator, SeaChem Prime is an excellent choice.

If you are registering ammonia in your tap water (likely an indication of chloramine) SeaChem Prime should be your choice for a “complete conditioner”.

As for all other claims of Prime (or any other conditioner), these are functions which basically none of us require. A properly maintained tank should not require the addition of “essential ions” via our water conditioner (please define these ions… can anyone?). “Electrolytes” is just a name for salts, vitamins are not stable when introduced into the water, aloe vera works by preventing wounds from drying out (not a problem when you are permanently submerged in water), other beneficial aspects of aloe vera are almost impossible to preserve in a bottle, aloe vera is not stable in water, and our fish should need no assistance in producing slime coat.

I use SeaChem prime exclusively in my Oscar Tank, secondarily due to its claims to either remove or detoxify nitrate. I can clarify with all certainty that it absolutely does not remove nitrate. It may, in some unknown fashion, partially detoxify nitrate, but it does not remove it. The primary reason I use Prime in my Oscar tank is that I perform very large water changes and have discovered the amount of slime coat lost by my Oscar fish, during water changes, is much reduced when using Prime opposed to other conditioners. I cannot qualify this beyond observation. The amount of slime coat trailing off my Oscars body is less when I use Prime than when using other conditioners. If I am completely honest, I also use Prime in my Oscar tank because I simply (and irresponsibly) feel like I’m cheating my Oscar out of something by using less than a “complete conditioner”.

In other tanks, I use API Tap Water Conditionerr, which is the most economical conditioner I've found but is not a "complete conditioner".


  • Complete Conditioner: Acts as a dechlorinator, breaks the chloramine bond, serves to detoxify ammonia, and binds heavy metals. 
  • Economical: 1 teaspoon treats 50 gallons. With most other conditioners, 1 teaspoon treats 10 gallons.
  • Made by SeaChem: SeaChem is a trustworthy company with a history of manufacturing quality products.


  • Questionable Claims: Sections of their marketing claims SeaChem Prime "removes" nitrate. It does not. Other components of their marketing claims it detoxifies nitrate, without knowing how. While yet other components of their marketing claims the product "enhances nitrate removal", again, without explaining how. After performing daily nitrate tests for years, I can absolutely state that Prime has no bearing on nitrate removal. For a forum thread discussing this in some detail, please click here:
  • Will Only Temporarily Detoxify Ammonia: This is not unique to SeaChem Prime, it is a universal truth amongst all conditioners. that detoxify ammonia. As a result, it's not really a "Con", I only mention it out of necessity. Many people think they dose with Prime and ammonia is permanently removed. First off, it's not removed, it's been converted to ammonium, which is a less toxic form. Secondly, this affect is only temporary, lasting from 12-24 hours. Hopefully this is sufficient to allow the biofiltration to remove the ammonia/ammonium. But in a cycling tank, this will not occur, so it is necessary to dose daily (at least).
  • Cost: A bottle of Prime will likely cost more than the bottle of conditioner next to it in the store. Even though it is more economical than the bottle next to it, the initial cost (albeit well worth it) may be higher.