Seachem MultiTest: Phosphate 75 Tests

• Natural seawater runs from under 0.01 up to about 0.3 mg/L phosphate – reef tanks generally do best kept at 0.2 mg/L or below for coral health.
• Phosphate itself is non-toxic to fish and most invertebrates, but keeping it under roughly 1 mg/L helps limit nuisance algae growth.
• Freshwater tanks often run higher than the kit's 3.0 mg/L range – dilute the sample with distilled or RO water and multiply the result to read a high concentration accurately.

• Over 75 tests per kit – around 82c per test at full retail price.
• Range 0–3.0 mg/L, detecting changes as fine as 0.001–0.1 mg/L on the colour chart.
• Six-cavity opaque white test plate – run and compare up to six samples at once.
• Sliding colour chart with a 5 cm viewing window for a cleaner colour match.
• Reference sample included to validate the kit whenever a result looks off.
• Freshwater and marine – one kit for the whole store's tank types.

• Phosphate Reagents 1 and 2
• Phosphate reference sample
• Stir rod and sample pipette
• Phosphate colour chart
• Multi-cavity test plate and instructions

Dose a sample with Phosphate Reagents 1 and 2 in order, stir, and read against the sliding colour chart within the stated development time. Freshwater samples reading off the top of the scale should be diluted with distilled or RO water – halve with an equal volume of distilled water and double the result, for example – rather than treated as unreadable.

Suitable for: reef, FOWLR, planted and community freshwater tanks tracking algae-feeding nutrients.

Not suitable for: reading freshwater phosphate accurately without dilution when levels run high, which is common in heavily-stocked or heavily-fed freshwater tanks – dilute first rather than assuming the kit is wrong.

Keep away from children. Reagent 2 contains sulfuric and molybdic acids and is corrosive – protect work surfaces, avoid skin and eye contact, and rinse any contact thoroughly with water.

• Seachem MultiTest Ammonia – phosphate and ammonia together cover the two most common causes of algae and livestock stress.
• A phosphate-removing media or reactor, for tanks where results consistently read high and a media-based export is wanted alongside water changes.

Ships as a standard parcel. Store reagents away from direct sunlight and extreme heat. Covered by the consumer guarantees under Australian Consumer Law in addition to Seachem's own guarantee.

Why is my freshwater phosphate reading off the chart?

Freshwater tanks frequently run higher phosphate than marine tanks and can exceed this kit's 0–3.0 mg/L range. Dilute the sample with distilled or RO water in a known ratio and multiply the result back up, rather than assuming the test has failed.

What phosphate level should I be aiming for in a reef tank?

Seachem's guidance is to keep reef systems at or below about 0.2 mg/L for coral health, with natural seawater typically under 0.3 mg/L.

Is phosphate actually harmful to my fish?

Not directly – phosphate is non-toxic to fish and most invertebrates at aquarium concentrations. The problem is indirect: elevated phosphate feeds nuisance algae, which affects the tank's appearance and can compete with corals and plants.

How many tests will I get from one kit?

Over 75, at roughly 82c per test – enough for regular weekly or fortnightly testing across a typical home aquarium for many months.

Can I use the same kit for freshwater and marine tanks?

Yes, the kit is rated for both – just remember freshwater samples may need diluting to fall inside the readable range.