API Phosphate Test Kit 1.25oz Fresh/Saltwater

• Measures phosphate 0–10.0 ppm – in either freshwater or saltwater, with separate colour charts for each.
• Two-reagent liquid test – Solution #1 and Solution #2 are added to a 5 mL sample in the supplied test tube; full colour develops in about 3 minutes.
• About 150 tests per kit – at the current price that works out to 43c per test.
• Freshwater and saltwater charts included – so a reef tank and a community tank read against the right reference.

Fill the supplied test tube to the 5 mL line with a water sample, add the reagents from Solution #1 and Solution #2 following the drop counts in the included instructions, cap and mix, then wait about 3 minutes for full colour to develop before comparing the sample against the freshwater or saltwater chart as appropriate.

API's own product page does not state a tests-per-kit figure. The approximately 150 figure above is consistent across independent retailers who reproduce the count printed on API's packaging; treat it as a close approximation rather than a guaranteed count.

Included:

• Capped glass test tube
• Phosphate Test Solution, Bottle #1
• Phosphate Test Solution, Bottle #2
• Freshwater and saltwater colour comparison charts
• Instruction booklet

Not included:

• A reference or calibration standard
• Any treatment for bringing a high reading back down

A rising phosphate reading traces back to feeding, waste or the tap water going into the tank. Routine water changes remove dissolved phosphate directly, and API Phos-Zorb is rated by API to adsorb phosphate and silicate out of the water column between changes if the reading keeps climbing.

Suitable for:

• Tracking down the cause of persistent nuisance algae
• Reef tanks monitoring nutrient export before it limits coral growth
• Fresh and saltwater fish-only and planted systems

Not suitable for:

• Measuring nitrate, ammonia or any parameter other than phosphate – pair it with API's other test kits for a full picture
• Instant diagnosis of a single algae outbreak – one reading is a snapshot, not a trend

• Keep both reagent bottles out of reach of children.
• Solution #1 contains sulfuric acid and causes severe burns. Never add water to this bottle, and avoid skin and eye contact.
• On eye contact, flush with water for 15 minutes, removing contact lenses after the first 5 minutes, and seek medical attention.
• On skin contact, wash thoroughly with soap and water.
• If swallowed, contact a physician or Poison Control immediately.

• API Phos-Zorb – the corrective product for a phosphate or silicate reading that won't come down with water changes alone.
• API Ammonia Test Kit Fresh/Saltwater – a tank running high on phosphate is often overdue for a full water-quality check, not just one parameter.
• API Copper Test Kit – worth running together on any tank with a history of medication use.

This is a consumable test kit, so no manufacturer warranty period applies. That does not affect your rights under the Australian Consumer Law: if the product is faulty, unsafe or not as described, you are entitled to a remedy.

Ships as standard freight.

Does this kit work in both freshwater and saltwater?

Yes. API supplies separate colour charts for freshwater and saltwater readings, using the same two reagents and procedure for both.

How many tests are in one kit?

Approximately 150, based on independent retailer listings that reproduce the count from API's packaging. API's own website does not publish a figure, so treat this as an approximation.

Why does my phosphate keep climbing even with water changes?

Feeding and waste generate phosphate continuously, so water changes only remove what's already dissolved at the time. If phosphate keeps returning between changes, a phosphate-adsorbing media run continuously will do more than changes alone.

Is Solution #1 dangerous to handle?

It contains sulfuric acid and causes severe burns on contact. Handle it away from children, avoid skin and eye contact, and never add water to the bottle itself.

What's a safe phosphate level for a reef tank?

API does not publish a target range on this kit's own instructions. Coral keepers commonly aim to keep phosphate low and stable rather than at a single number – if you're chasing a specific target for SPS or LPS, that's worth confirming with your coral supplier rather than this kit's packaging.