Keep nuisance algae under control and maintain clean, stable water with the API Phosphate Test Kit.

This easy to use liquid test kit allows you to quickly measure phosphate (PO4) levels in your saltwater or reef aquarium. Elevated phosphate can contribute to algae growth and poor water quality, making regular testing essential for maintaining a healthy tank.

Designed for simplicity and reliability, this kit provides clear, accurate results to help you monitor and manage your aquarium with confidence.

What It Tests

• Phosphate (PO4) levels in saltwater and reef aquariums

Why It Matters

Excess phosphate can lead to unwanted algae growth and negatively impact coral health.
By monitoring phosphate levels regularly, you can take action early and maintain a cleaner, more balanced aquarium.

Perfect For

• Reef aquariums (soft coral, LPS, and SPS systems)
• Controlling algae growth
• Routine water testing and maintenance
• Beginner and intermediate reef hobbyists

What’s Included

• Phosphate test solution
• Glass test tube with cap
• Color comparison chart
• Step by step instructions

Pro Tip

For best results, pair this test kit with calcium and alkalinity testing to maintain balanced water chemistry and support a healthy reef environment.