Seachem Clarity

• Two agents, one bottle – precipitating and flocculating chemistry together, which is why it copes with bacterial and algal clouding as well as ordinary dust and grit.
• Clears in 1–2 hours – you can dose it before dinner and have a clear tank by the end of the evening.
• Reef and plant safe as directed – the polymer does not strip soluble nutrients or trace minerals, so dosing schedules and fertiliser routines are unaffected.
• Repeatable every 24 hours – stubborn blooms can take more than one dose without a waiting period between them.
• Works in fresh and salt – one product for the whole fishroom.
• Three sizes – 100 mL, 250 mL and 500 mL, covering a single tank through to a multi-tank rack.
• From 1c per litre – dosed at the label rate, the 100 mL bottle works out to about 1c per litre treated; the 250 mL and 500 mL bottles drop to under 1c per litre.

Seachem Clarity binds microscopic suspended particles into larger clumps that mechanical media can finally catch. The particles are not destroyed – they are made big enough to be filtered out. That distinction matters, because without fine mechanical media in the flow path there is nothing to catch them and the tank will not clear.

Expect the water to look worse before it looks better. A short-lived increase in cloudiness immediately after dosing is the flocculant doing its job.

Dose 1 capful (5 mL) per 80 L of aquarium water. Add it near the filter intake so it reaches the mechanical media quickly. Repeat every 24 hours if needed.

Fine filter floss is the right media for this. A coarse sponge will let most of the clumps straight through. Check the floss once the tank clears – it may need rinsing or replacing more than once while the clumps are loading it up.

In very soft, lightly buffered water, Seachem advises starting at a quarter to a half dose and watching the effect on pH before going to the full rate.

Water treated per bottle

Seachem Clarity is an occasional-use product for most people, so buy for the number of events rather than the year. A 100 mL bottle gives a 200 L tank eight full doses, which is several separate clouding episodes with repeats.

The 250 mL and 500 mL bottles make sense if you run multiple tanks, keep sand you disturb regularly, or set up new tanks often enough to meet the two-week bacterial bloom on a schedule. There is also a 325 mL bonus bottle that carries 30% more than the standard 250 mL fill when it is in stock.

Suitable for

• New-tank bacterial blooms – the milky haze of the first fortnight
• Fine dust after adding or disturbing sand and substrate
• Green water and other free-floating algal blooms
• Debris and grit after a rescape or a heavy gravel vacuum
• Reef tanks, planted tanks and freshwater community tanks alike

Not suitable for

• Tanks with no mechanical filtration running – nothing will collect the clumps
• Yellow or tea-coloured water from dissolved organics or tannins – that is a job for Purigen or MatrixCarbon
• Fixing the cause of a bloom – Clarity clears the symptom, not the nutrient, light or maturity problem behind it
• Coarse sponge-only filtration, which lets most of the clumps pass

• Keep out of reach of children and away from food.
• Do not exceed the stated dose; more flocculant does not clear water faster and loads the filter harder.
• Watch the filter after dosing – heavily loaded floss can restrict flow.
• Store sealed and out of direct sunlight.
• Seachem publishes a Safety Data Sheet for this product at sds.seachem.com.

• Seachem Purigen – for the dissolved organics and yellowing that a clarifier cannot touch
• Seachem MatrixCarbon – chemical polish alongside the mechanical clearing
• Seachem The Bag – holds media in the flow path where the clumps travel
• Seachem Stability – for the underlying cause when the haze is a new-tank bacterial bloom
• Seachem Prime – the conditioner for the water change that usually follows
• Seachem Clarity 325 mL bonus bottle – the same formula with 30% extra when promotional stock is available

This is a consumable water treatment, so no manufacturer equipment warranty applies. Your rights under the Australian Consumer Law apply in addition to anything the manufacturer states, including the guarantees that goods are of acceptable quality and fit for the purpose described.

All three sizes are under one litre and ship as ordinary parcels. Bottles are supplied sealed.

Why did the water get cloudier after dosing Clarity?

That is the product working. The flocculant binds fine suspended particles into larger clumps, and the tank looks hazier for a short period while that happens. Clearing normally follows within one to two hours.

Does Clarity work without a filter?

No. Clarity makes particles large enough to be caught by mechanical media, but something has to catch them. Without fine filter floss or an equivalent in the flow path, the clumps stay in the water column.

Is Clarity safe in a reef tank or a planted tank?

Yes, used as directed. Seachem states the polymeric flocculant is both reef safe and plant safe, and that it does not remove soluble nutrients or trace minerals, so fertiliser and supplement routines are unaffected.

How often can Clarity be dosed?

Every 24 hours as required. Persistent bacterial blooms in a new tank can take several rounds, and the underlying cause is biofilter maturity rather than anything the clarifier can fix.

Will Clarity fix green water permanently?

It will clear the green tint by clumping the free-floating algae for the filter to remove, but the bloom returns if the light and nutrient conditions that caused it are unchanged. Treat it as a reset, not a cure.

Can Clarity be used in very soft water?

Yes, with care. Seachem recommends starting at a quarter to a half dose in soft, lightly buffered water and observing the effect on pH before moving to the full rate.