Seachem AmGuard

A general water conditioner is a water-change product. AmGuard is a problem product.

You use it when a test kit or an Ammonia Alert says free ammonia is present and climbing, and it needs to be gone before the fish take damage.

The difference that matters is how it is dosed. AmGuard can be dosed against a measured ammonia figure rather than tank volume alone – 5 mL per 40 L removes 1 mg/L. That turns an emergency into arithmetic instead of guesswork.

The situations it is built for: a tank still cycling, a filter that crashed after a course of medication, an overstocked quarantine tank, a long power failure, or a dead fish found late.

• Acts in minutes, holds for 72 hours – the bound ammonia does not release back into the water inside that window
• Dose to a number – 5 mL per 40 L removes 1 mg/L of measured ammonia, so a test reading tells you exactly how much to add
• Does not alter pH – no second problem created while solving the first, and nothing to undo in a buffered tank
• Removes chlorine and chloramine too – usable on the replacement water during the same emergency
• Freshwater and marine – one bottle covers both systems
• Four sizes to 4 L – the 4 L is a fishroom, breeder or shop size rather than a display-tank one
• Under 1c per litre – at the standard 200 L dose, every size works out to under one cent per litre of water treated

With no test kit at all

One capful (5 mL) for every 200 L, daily or as needed.

With an Ammonia Alert sensor

With a liquid ammonia test

5 mL for every 40 L removes 1 mg/L (ppm). For readings in between, Seachem publishes the formula: multiply 0.125 by the ammonia reading in mg/L and by the tank volume in litres, and the answer is millilitres to add.

A 250 L tank reading 0.4 mg/L needs 0.125 × 0.4 × 250, which is 12.5 mL.

Keep dosing daily until the biofilter is handling the load on its own. AmGuard buys time; it is not a substitute for cycling the tank.

Worked from the standard 5 mL per 200 L dose. In a genuine emergency at the Toxic-level rate you will get through it two and a half times faster – that last column is why the 4 L size exists. Cost per litre is at the standard dose; every size lands under a cent per litre of water treated.

Seachem's instruction is explicit: if water temperature is above 30 °C, do not use AmGuard. In a Queensland summer that is not a footnote. A tank sitting at 31 °C in February is a tank where this product is off the table, and the answer that day is a water change with aeration instead.

The second caution is oxygen. Large doses can reduce dissolved oxygen. Do not use it on a tank that is already oxygen-starved, and do not stack it with other oxygen-reducing products at the same time. Run an airstone while you dose.

This catches people out every time, so it is worth understanding before it happens.

Standard liquid ammonia tests work by raising the sample's pH to somewhere between 12 and 14. AmGuard cannot hold ammonia bound at that pH, so the test releases what the product just locked up and reports it back as a positive.

The ammonia in the vial is real. It is simply not in the form that exists in your tank. Judge the tank instead by whether the fish are recovering and by an Ammonia Alert, which responds only to free ammonia and is not fooled the same way.

Suitable for: freshwater and marine aquariums · tanks still cycling · quarantine and hospital tanks · recovery after a filter crash or a medication course · emergency use when a test shows free ammonia · treating replacement water for chlorine and chloramine.

Not suitable for: water above 30 °C · tanks already low on dissolved oxygen · use alongside other oxygen-reducing products · as a replacement for cycling a tank or for water changes · as the routine every-water-change conditioner, which is what Seachem Prime and Seachem Safe are for.

• Seachem Ammonia Alert – the sensor the Alert, Alarm and Toxic dosing table is written around, and the one reading that dosed AmGuard does not confuse
• Seachem MultiTest: Ammonia – gives you the mg/L figure the measured dose needs
• Seachem Stability – rebuilds the biological filter that failed in the first place
• Seachem Prime – the routine conditioner for every water change
• Seachem Matrix – biological media, if the crash was a capacity problem rather than a one-off
• The full Seachem range – water care, media and test kits

Sold with the manufacturer's shelf life; no separate warranty term is published for a liquid conditioner. Your rights under the Australian Consumer Law apply regardless and cannot be excluded. A safety data sheet is published by Seachem at sds.seachem.com. The 100 mL to 500 mL sizes ship as a standard parcel; the 4 L is a bulk liquid and travels as heavy freight.

How much AmGuard do I use for 1 ppm of ammonia?

5 mL for every 40 litres removes 1 mg/L (ppm). For any other reading, multiply 0.125 by the ammonia in mg/L and by the volume in litres to get the dose in millilitres.

How long does AmGuard keep ammonia detoxified?

Around 72 hours, and it does not degrade inside that window. If ammonia is still being produced after three days, dose daily until the biofilter catches up.

Why does my ammonia test still show a reading after dosing?

Standard ammonia tests raise the sample's pH to 12–14, and AmGuard cannot hold ammonia bound at that pH. The test releases the bound ammonia and reports it. It is a false positive for tank conditions, not a failed dose.

Can I use AmGuard in a saltwater tank?

Yes. It is formulated for both freshwater and marine aquariums.

Does AmGuard change pH?

No. Seachem states it does not alter pH, which is why it can go into a buffered tank without a correction afterwards.

Is there a temperature it should not be used at?

Yes. Seachem's instruction is not to use it if water temperature is above 30 °C. In a hot spell, a water change with aeration is the safer response.

Can I use it every water change instead of Prime?

It would work, but it is not what it is for. AmGuard is an ammonia product dosed against a reading; a routine conditioner is the cheaper and simpler tool for ordinary water changes.