Seachem Prime Aquarium Fish Tank Water Conditioner 500ml

Seachem Prime 500ml is a highly concentrated aquarium water conditioner ideal for large aquariums, multiple tanks, fish rooms and fishkeepers carrying out frequent water changes.

Prime removes chlorine and chloramine from tap water while temporarily detoxifying ammonia, nitrite and nitrate, helping protect aquarium livestock during water changes, new tank setup and temporary water-quality problems.

With a standard dose of just 5ml per 200 litres, one 500ml bottle can treat up to 20,000 litres of aquarium water.

Key Features and Benefits

• Highly concentrated aquarium water conditioner
• 500ml bottle treats up to 20,000 litres
• Removes chlorine from tap water
• Removes chloramine
• Temporarily detoxifies ammonia
• Temporarily detoxifies nitrite and nitrate
• Helps detoxify heavy metals commonly found in tap water
• Excellent for large aquariums and multiple tanks
• Ideal for regular water changes
• Suitable for freshwater and marine aquariums
• Can be used during aquarium cycling
• Non-acidic and will not significantly affect pH
• Economical choice for high-volume aquarium maintenance

Ideal for Large Aquariums & Multiple Tanks

The 500ml size is an excellent option for aquarium keepers who use water conditioner regularly.

It is particularly suitable for:

• Large display aquariums
• Multiple aquarium setups
• Fish rooms
• Breeding systems
• Cichlid aquariums
• Planted tanks
• Aquarium maintenance routines
• Frequent or large water changes

Because Prime is extremely concentrated, only a small amount is required each time tap water is added.

How Much Water Does Seachem Prime 500ml Treat?

At the standard dose:

5ml treats 200 litres

This means a 500ml bottle can treat approximately:

20,000 litres of aquarium water

That is equivalent to approximately 100 standard 200-litre treatments.

Seachem Prime Dosage

For normal water conditioning:

Use 5ml for every 200 litres of new water.

Approximate dosing examples:

For smaller doses, each thread inside the Seachem cap is approximately 1ml.

Why Use Seachem Prime?

Tap water may contain chlorine or chloramine as part of municipal water treatment.

These disinfectants can be harmful to aquarium fish and may also affect beneficial bacteria within biological filtration.

Prime conditions replacement tap water before it affects aquarium livestock or filtration.

It can be used whenever:

• Setting up a new aquarium
• Performing a water change
• Adding replacement water
• Cycling a new aquarium
• Managing temporary ammonia or nitrite problems

Prime & Chloramine

Prime & Ammonia

Prime temporarily converts or binds ammonia into a less toxic form.

It does not permanently remove ammonia from the aquarium.

The biological filtration system can continue processing the detoxified ammonia through the nitrogen cycle.

This can provide additional protection during:

• Aquarium cycling
• Temporary ammonia spikes
• Increased fish load
• New aquarium setup
• Unexpected water-quality problems

Prime should not replace regular water testing, suitable filtration or good aquarium maintenance.

Prime & Nitrite

Prime can also temporarily detoxify nitrite.

This can be particularly useful during a new aquarium cycle or following disruption to biological filtration.

Seachem advises that Prime may be dosed at higher levels in emergency nitrite situations, but normal aquarium maintenance should always focus on identifying and correcting the cause of elevated nitrite.

Using Prime During Water Changes

Prime is ideal for routine water changes.

For best results, add Prime to replacement tap water before it enters the aquarium.

If Prime is added directly to the aquarium, calculate the dose based on the aquarium's total water volume rather than only the amount being replaced.

Seachem Prime During Aquarium Cycling

Prime can be used while establishing the biological cycle in a new aquarium.

The ammonia and nitrite temporarily detoxified by Prime remain available for beneficial bacteria to process.

Prime can be paired with Seachem Stability to help establish and support biological filtration during aquarium setup.

Suitable for Freshwater & Marine Aquariums

Seachem Prime can be used in both freshwater and marine aquariums.

It is suitable for aquarium setups including:

• Tropical community tanks
• Cichlid aquariums
• Planted aquariums
• Aquascapes
• Betta tanks
• Shrimp aquariums
• Large display tanks
• Marine aquariums
• Multi-tank fish rooms

Economical for Frequent Water Changes

The 500ml bottle is particularly economical for customers who use Prime frequently.

For example:

A 200L water change uses 5ml.

A 400L water change uses 10ml.

A 500ml bottle therefore provides enough Prime for approximately:

• 100 × 200L treatments
• 50 × 400L treatments
• 20,000L total treatment volume

This makes the larger bottle a practical choice for customers maintaining several aquariums or large-volume systems.

Does Seachem Prime Affect pH?

Prime is non-acidic and should not significantly affect aquarium pH when used according to directions.

It can therefore be used across a wide range of aquarium setups without deliberately altering the aquarium's target pH.

Why Does Seachem Prime Smell Like Sulphur?

A sulphur-like odour from Prime is completely normal.

The smell does not indicate that the product has spoiled or become ineffective.

Keep the bottle closed when not in use and follow the manufacturer's dosing instructions.

Product Specifications

Frequently Asked Questions

How much water does Seachem Prime 500ml treat?

At the standard dose of 5ml per 200 litres, a 500ml bottle treats approximately 20,000 litres of water.

How much Seachem Prime should I use?

Use 5ml for every 200 litres of water, or approximately 1ml per 40 litres.

Is Seachem Prime 500ml good for large aquariums?

Yes. The 500ml bottle is particularly economical for large tanks, multiple aquariums and frequent water changes.

Does Prime remove chlorine?

Yes. Seachem Prime removes chlorine from tap water.

Does Prime remove chloramine?

Yes. Prime removes chlorine from chloramine and temporarily detoxifies the resulting ammonia.

Does Seachem Prime remove ammonia?

Prime temporarily detoxifies ammonia rather than physically removing it. Biological filtration continues processing the ammonia.

Can Seachem Prime be used while cycling an aquarium?

Yes. Prime can be used during aquarium cycling to temporarily detoxify ammonia and nitrite while still allowing them to remain available to beneficial bacteria.

Can I add Prime directly to my fish tank?

Yes. Prime may be added directly to the aquarium. If dosing this way, base the amount on the aquarium's total water volume.

Can Seachem Prime be used with Stability?

Yes. Prime and Stability work well together, particularly during aquarium setup, cycling and when adding new fish.

Why does Seachem Prime smell like sulphur?

A sulphur-like smell is normal for Prime and does not mean the product is faulty.

Is Seachem Prime suitable for freshwater and saltwater tanks?

Yes. Prime is suitable for both freshwater and marine aquariums.