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Is Seachem Prime any good?

If you are looking for a water conditioner to treat your new water before it goes into your fish tank, you will most likely come across Seachem Prime in your research.

You can check out Aquarium Blueprints’ review of the best selling aquarium water conditioner below.

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Pricing and Size Options

Seachem Prime has multiple size options: 50 mL, 100 mL, 250 mL, 500 mL, 1 L, 2 L and 4 L. You can see how much gallons of water in you fish tank that each bottle size can treat below:

  • 50 mL: 500 gallons
  • 100 mL: 1,000 gallons
  • 250 mL: 2,500 gallons
  • 500 mL: 5,000 gallons
  • 1 L: 10,000 gallons
  • 2 L: 20,000 gallons
  • 4 L: 40,000 gallons

You can check out the current price tags for each container size with this link on Amazon. (#CommissionsEarned).

Does Seachem Prime has an expiration date?

According to Seachem, the Prime conditioner does not have a expiration date. With that said, you should take some care when it comes to storing the product. We recommend keeping the solution in a temperature and humidity controlled environment. Furthermore, you should keep the lid on the bottle tightly closed when you are not using the product.

What does it mean if you find black specks in your Prime bottle?

The occurrence of black specks on the bottom of your bottle is perfectly normal. They won’t have any effect on the performance of the conditioner.

What if your Prime smell different?

Prime normally have a strong sulfur smell. There have been reports that the conditioner will also give off different scents such as garlic. According to Seachem, the different aromas are a result of the manufacturing process. The company also stated that the odor have no effect on how the product functions.


What we loved most about Seachem Prime is its versatility. The product’s main functionality is that it will remove chlorine and chloramine from your tap water. At the same time it will also help detoxify any heavy metals to make your water safe for fish in your freshwater, saltwater and/or brackish water tanks.

Furthermore, the same conditioner is going to detoxify ammonia, nitrites and nitrates. Both ammonia and nitrites are highly toxic at even low levels of concentration. Nitrates can also be dangerous at concentrations of above 40 ppm with extended exposure. Prime will bind with the aforementioned compounds, making them non-toxic to your fish over a 48-hour period.

Due to its nature of being able to detoxify nitrogen compounds, we like to dose Prime on a daily basis over the course of a week anytime we add new fish to our aquarium. Doing so ensure us that any spikes to ammonia, nitrite and/or nitrate will be harmless to our aquatic pets while our beneficial bacteria continues to grow to accommodate the extra wastes being introduced.

Last but not least, we also liked that Prime won’t change the pH of your water parameters, as sudden and significant pH swings can cause stress and sickness to your fish. Brackish and saltwater fish keepers should also be happy to learn that this chemical won’t over-activate your skimmers.


One big con with the conditioner is, of course, the sulfur odor. You will get a rotten egg smell from your aquarium after dosing the chemical for around 48 hours.

Another issue with Prime is that it can give false ammonia readings on your water testing kits, most notably the API Master Test Kit. This is because the kits use Nessler chemistry, which will give false positives to chemicals like Seachem Prime that act as a reducing agent or ammonia binder.

To get an accurate reading, we recommend waiting 48 hours after adding Prime to your tank. By that time, the conditioner should completely dissipate from your water.

It should also be noted that Seachem Prime contains complexed hydrosulfite salts, which is hazardous to humans. If you or a loved one somehow consume the liquid, then you should seek medical assistance immediately.


The amount of recommended dosage of Seachem Prime depends on what you want the conditioner to accomplish.

Before we start discussing the directions, we first want to note that you should dose based on the entire volume of water your tank is capable of holding. For example, if you have a 55 gallon aquarium, then you should add enough of the conditioner to treat all 55 gallons. This is to keep dosing less complicated than it needs to be. Not to mention that a little overdose of Prime won’t harm your fish at all

When adding the Prime during a water change, we prefer adding the solution directly into the tank before adding the new water from our tap or any other source. We have been doing this for years and haven’t run into issues when it comes to water changes affecting our pet fish.

In a vast majority of cases, you can overdose Seachem Prime by 5 times the normal amount and your fish will still be safe. When it comes to this product, it is always better to overdose as opposed to under-dose. Even if you feel that you put way too much Prime in your tank, you can do a simple water change to bring the concentration down to a level you are more comfortable with.

One last note is that the directions are slightly different with the 50 mL bottle when compared to the bigger sized options. With the 50 mL bottle, you have to add two drops to treat every gallon. For everything else, you dose based on capful with the cap that comes with the bottle. The cap sizes are also different with the bigger bottles. The 100 mL, 250 mL and 500 mL caps can hold 5 mL while the 1 L, 2 L and 4 L caps can hold 10 mL. Our directions assume that you have a bottle of the product that is at least 100 mL.

Removing chlorine and chloramine as well as detoxifying heavy metals, ammonia, nitrites and nitrates

To remove chlorine and chloramine, in addition to detoxifying heavy metals, ammonia, nitrites and nitrates, you should dose 5 mL for every 100 gallons.

You should keep in mind that Seachem Prime won’t get rid of ammonia, nitrites and nitrates from your water. The chemical simply binds them to a non-toxic form for up to 48 hours. You need beneficial bacteria, live plants and water changes to get rid of ammonia, nitrites and nitrates. If you are having issues with these nitrogen compounds, mainly ammonia and nitrites, then we recommend dosing Prime daily along with doing partial water changes until you have enough beneficial bacteria and/or live plants to get rid of the toxins.

Removing high chloramine concentration

If you have an unusually high amount of chloramine in your water, it is recommended that you double the normal amount of dosage with the solution.

Detoxifying high nitrite concentration

To detoxify high amounts of nitrite in an emergency, Seachem suggests dosing 5 times the normal dosage in your tank water.

Removing low ammonia and/or chlorine at high temperatures

If you have low concentration of ammonia and/or chlorine at a temperature higher than 86 Fahrenheit (or 30 Celsius), then you should use half the amount of the normal dosage amount.


Not only do we think Seachem Prime is the best aquarium water conditioner on the water, we also viewed it as an essential tool for the aquarium hobby due to its ability to detoxify ammonia, nitrites and nitrates.