How to Dosing for Reef Keeping - Step by Step
Step-by-step guide to Dosing for Reef Keeping. Includes time estimates, tips, and common mistakes to avoid.
Consistent dosing is one of the biggest keys to long-term reef stability, especially in tanks with stony corals, coralline algae, and clams that steadily consume alkalinity, calcium, and magnesium. This step-by-step guide walks you through how to measure demand, choose between two-part and kalkwasser, and set up a dosing routine that keeps parameters stable instead of chasing swings.
Prerequisites
- -A fully cycled saltwater reef aquarium with stable salinity, ideally 1.025-1.026 SG
- -Reliable test kits or digital testers for alkalinity, calcium, and magnesium
- -A refractometer calibrated with 35 ppt solution
- -Dosing solution on hand - either two-part alkalinity and calcium supplements, or kalkwasser powder
- -Magnesium supplement if Mg is below target range
- -Graduated measuring container or dosing syringe marked in mL
- -Auto top off system if planning to use kalkwasser
- -Basic understanding of target reef parameters, such as alkalinity 7.5-9.0 dKH, calcium 400-450 ppm, and magnesium 1250-1400 ppm
- -A logbook or tracking app to record daily test results and dosage changes
Before adding anything, decide on stable target numbers that fit your livestock and salt mix. For most mixed reefs, aim for alkalinity between 8.0 and 8.5 dKH, calcium between 420 and 450 ppm, and magnesium between 1300 and 1400 ppm. Keeping these values steady is more important than hitting the highest possible number, especially for SPS corals that react badly to rapid swings.
Tips
- +Match your target alkalinity to the level your tank naturally runs well at, rather than forcing a dramatic change.
- +If nutrients are very low, avoid pushing alkalinity above about 8.5 dKH to reduce the risk of burnt tips on SPS.
Common Mistakes
- -Choosing target numbers based on someone else's tank without considering your own nutrient levels and coral mix.
- -Trying to raise alkalinity, calcium, and magnesium all at once before confirming actual test results.
Pro Tips
- *Use alkalinity as your primary control parameter, because it responds fastest and gives the earliest warning that your dose is off.
- *If you run kalkwasser, keep the reservoir covered to reduce CO2 exposure and preserve potency.
- *Calibrate dosing pumps every few months, because pump tubing wear can slowly change the delivered mL per day.
- *If pH already runs 8.3 to 8.5, increase kalkwasser cautiously since too much can push pH high enough to stress livestock.
- *When coral demand becomes too high for kalkwasser alone, use kalkwasser for baseline support and add two-part to cover the remaining alkalinity and calcium consumption.
Keep a clean backup log for test day.
The Printable Reef Logbook gives you water testing, dosing, maintenance, and livestock worksheets you can print or save as a PDF.