Phosphate at 0.03–0.08 ppm is the sweet spot for vibrant SPS color. Standard hobby kits cannot resolve below 0.1 ppm. The Hanna Checker ULR (HI736) reads to 0.01 ppm with lab-grade reproducibility.

Workflow

Test 2x/week, log readings in the Water Parameter Tracker, dose phosphate remover (or feed less) when above 0.10 ppm.

Related reef reading

Reef tools mentioned in this article

🪸

Reef Tank Match Quiz

Find the right reef archetype for your space and budget.

Start quiz →
⚙️

Reef Equipment Planner

Generate a complete equipment shortlist for your build.

Open planner →
🧪

Water Parameter Tracker

Log every reading. Catch problems before livestock notice.

Open tracker →