Red Sea Marine Care Calcium Test Kit
Water type
Saltwater + Reef
Red Sea Marine Care Calcium Test Kit
Know your calcium before you dose blind. The Red Sea Marine Care Calcium Test Kit measures calcium in marine and reef aquariums using a syringe-based titration — count the drops, read the number straight off the syringe, no colour matching to squint at. Calcium is the number one building block for coral and coralline growth, and it drops fastest in the tanks doing the most growing.
Key features
- 75 titration tests per kit — enough for weekly testing in a busy reef tank for well over a year.
- Selectable resolution — read to 30 ppm for a quick weekly check, or 15 ppm when you need to confirm a dosing change actually moved the number.
- Titration method — a 5 mL syringe doses reagent drop by drop until the sample changes colour; the drop count is the reading.
- Conversion chart included — the drop count reads straight across to ppm without doing the maths yourself.
Specifications
| Property | Value |
|---|---|
| Measures | Calcium (Ca) |
| Method | Titration (syringe drop-count) |
| Resolution | Selectable 15 ppm or 30 ppm |
| Tests per kit | 75 |
| Water type | Marine and reef |
| Storage | Sealed, 15–25°C, use before the expiry date printed on the pack |
What's included / Not included
The kit includes Reagent A (25 mL), Reagent B (20 g), Reagent C (50 mL), a 5 mL syringe, a glass test vial, a measuring spoon and printed instructions with a conversion chart — everything needed for 75 tests. It does not include a magnesium or alkalinity test — calcium, alkalinity and magnesium move together in a reef tank, and testing only one gives an incomplete picture.
Suitable for, and not suitable for
Suitable for fish-only, mixed reef and SPS-dominated marine systems — anywhere coralline algae, corals or clams are drawing calcium out of the water. Less useful on a fish-only tank with no calcifying life, where calcium rarely needs tracking.
Target ranges
| System type | Target calcium |
|---|---|
| FOWLR (fish only with live rock) | 380–420 mg/L — stability matters more than hitting a specific number |
| Mixed reef / soft and LPS coral | 400–450 mg/L |
| SPS-dominated reef | 420–450 mg/L, held alongside alkalinity 7–9 dKH and magnesium 1,300–1,400 mg/L |
These are marine and reef target ranges. Calcium is not a parameter tracked in freshwater community, planted or African cichlid tanks, so no freshwater target range applies to this kit.
What to do when the reading is out of range
Low calcium is corrected with a calcium supplement such as Red Sea Reef Care Calcium+ Foundation A, dosed alongside alkalinity and magnesium rather than on its own — moving one element without the others throws off the balance between them. Retest a few days after any dosing change rather than the same day; calcium takes time to equilibrate.
Care and storage
Keep sealed, store between 15–25°C out of direct sun, and check the expiry date printed on the pack before trusting an older kit's result.
Warranty and delivery
Covered by the consumer guarantees under Australian Consumer Law, in addition to any manufacturer undertaking. Standard parcel freight — no special handling required.
Goes well with
- Red Sea KH/Alkalinity Pro Testing Kit — test alongside calcium; the two parameters move together.
- Red Sea Marine Care Magnesium Test Kit — magnesium stabilises both calcium and alkalinity.
- Red Sea Reef Care Calcium+ Foundation A — the matching dosing solution when calcium reads low.
Common questions
How often should I test calcium?
Weekly in a growing reef tank, fortnightly to monthly in a stable fish-only or soft-coral system.
Why does my calcium keep dropping?
Growing coral and coralline algae consume calcium continuously — the more growth in the tank, the faster it needs replacing.
Should I test calcium on its own, or with alkalinity and magnesium?
Test all three together where possible. Calcium and alkalinity are inversely linked through the calcification process, and magnesium keeps both in solution — a change in one without checking the others can send you chasing the wrong number.
Can I use this kit on a freshwater planted tank?
It's formulated and calibrated for marine calcium ranges (350–500+ mg/L) and isn't the right tool for the much lower calcium levels relevant to freshwater planted tanks.
