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Seachem AmGuard vs. Seachem Prime: Which is Better at Detoxifying Ammonia?

Ammonia is very toxic to fish even in small amounts. If your aquarium has not been properly cycled, then you could get ammonia spikes. One of the potential fixes to this issue is by using a water conditioner. Seachem has two products that will detoxify ammonia. So which of these is better, AmGuard or Prime? You can find out in this comparison guide.


The Seachem AmGuard Water Conditioner is available in four different bottle sizes: 100 mL, 250 mL, 500 mL and 4 L.

The Seachem Prime Water Conditioner is available in seven different sizes: 50 mL, 100 mL, 250 mL, 500 mL, 1 L, 2 L and 4 L.


You can check out the current price tags for the two products on Amazon with the following links:

Detoxifying Ammonia

When compared to Seachem Prime, the Seachem AmGuard is better at detoxifying ammonia at higher concentrations.

In order to detoxify 2 ppm of ammonia, you have to overdose Prime by 5 times the normal amount. With Am Guard, you only need to use a normal dose to achieve the result.

Not to mention that Prime can only treat 2 ppm of ammonia at most. With AmGuard, you can go treat more than 5 ppm.

Detoxifying Length

The Seachem Prime Conditioner will detoxify ammonia for up to 48 hours. The Seachem AmGuard Conditioner’s detoxification length is longer at up to 72 hours.

Temperature Limitations

Both products have limitations when it comes to temperature. If your tank water is more than 86 °F (or 30 °C), then you have to decrease the normal dosage amount by half with Prime.

Seachem recommends that you don’t use Am Guard at all if the temperature of your aquarium is over 86 °F (or 30 °C).

The water conditioners will deplete oxygen from the water. In temperatures less than 86 °F (or 30 °C), there shouldn’t be any problems unless you severely overstocked your tank with fish.

However, the higher temperatures will lead to less oxygen in your water. So, you could harm your fish by overdosing Prime, or simply dosing AMGuard, if your tank has a temperature greater than 86 °F (or 30 °C).

Detoxifying Nitrite and Nitrate

Only Seachem Prime will be able to detoxify nitrite and nitrate in addition to ammonia. This is vitally important because the ammonia spike will turn into a nitrite spike. So, even if you use AMGuard, your fish will still be in danger due to the presence of nitrites.

Removing Chlorine and Chloramine

Both Prime and AM Guard are able to remove chlorine and chloramine from water. These chemicals usually appear in tap water to kill bacteria in order to make the water safe to drink for humans.

However, chlorine and chloramine will harm your fish as well as the beneficial bacteria needed to break down fish wastes.

Detoxify Heavy Metals

Another advantage Prime has over AMGuard is that it can also detoxify small traces of heavy metals such as arsenic, copper, lead and mercury.

Natural Slime Coat Production

Using Prime will also trigger your fish to produce a healthy mucus for their slime coat. The coating will prevent infections.


In terms of dosage, the AMGuard has the advantage when it comes to detoxifying ammonia. You only have to use 50 mL of the conditioner to detoxify 2ppm of ammonia in a 50 gallon tank.

For Prime, you need 250 mL to detoxify 2ppm of ammonia for a 50 gallon aquarium.

Can you use AmGuard and Prime at the same time?

You will be able to use Seachem AmGuard and Seachem Prime as long as you have a good filter flow in your aquarium. When dosing, you should spread out your doses of the two products by at least an hour.


Seachem AmGuard is the better of the two products at detoxifying ammonia as you can treat for more than 2ppm. In comparison, Seachem Prime can only treat 2ppm of ammonia at the most.

With that said, Prime has a lot of other features, the most important of which is its ability to also detoxify nitrite. If you have ammonia, then you most likely need to treat nitrite, which is also toxic to fish, as well. Not to mention that prime will also detoxify nitrates and heavy metals in addition to triggering your fish to develop healthy slime coats.

Overall, we recommend using Seachem Prime over Seachem AmGuard if you have an ammonia level of 2 ppm of less. If you have a higher level, then we suggest first dosing AmGuard and then dose Prime one hour later so that you can detoxify the high amounts of ammonia in addition to the nitrites.

If you are interested, you can purchase either of the two products on Amazon with the following links:


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