
Calcium
G2000 · 500ml
Essential for coral growth and skeletal formation in reef aquariums. Calcium is one of the most critical elements for a thriving reef aquarium. It is an essential building block in...
Or build it into a bundle — save up to 6% ↓What it is, and who it is for.

Essential for coral growth and skeletal formation in reef aquariums.
Calcium is one of the most critical elements for a thriving reef aquarium. It is an essential building block in the formation of calcium carbonate, which makes up the skeletons of SPS and LPS corals, as well as the shells of invertebrates and coralline algae. Without sufficient calcium, coral growth slows, and overall health can become compromised.
Maintaining stable calcium levels ensures consistent skeletal growth, vibrant coloration, and strong biological processes throughout your reef system. Together with balanced alkalinity and magnesium levels, calcium forms the backbone of a healthy and stable marine environment.
Key Benefits:
• Supports coral skeletal and shell formation
• Promotes healthy growth of SPS, LPS, and coralline algae
• Enhances overall reef stability and vitality
• Prevents calcium depletion that can slow coral growth
• Works synergistically with alkalinity and magnesium
Recommended Levels:
420–460 ppm
Directions for Use:
Add 5 ml of Calcium per 100 L (25 gal) of aquarium water to raise calcium levels by 7.5 mg/L (ppm).
Test calcium levels regularly and adjust dosage as needed to maintain stability.
Build around the Calcium.
It's already in your system below. Add the flow, filtration and dosing around it and the discount starts working — tiers climb as the build grows, and the reef meter fills with it.
Pick the right one, not the biggest one
The honest line-up from dosing & testing. Most buyers reading this page should buy the middle column.
Asked before checkout
The questions our support inbox actually gets.
Does it ship quickly?+
Orders placed before 2 PM ET on a business day leave the same day. Tracking is emailed the moment the label prints.
What if it's the wrong fit for my tank?+
Return it. 30 days, no restocking fee, refund to the original payment method. Better: tell us your tank first and we'll spec the system for free — half of all returns are sizing problems.
Who handles the warranty?+
We do. Everything carries the manufacturer's warranty and we run the claim for you — one email to us instead of a ticket queue.
How does the bundle discount work?+
Add items in the bundle builder: 2+ items saves 5%, 3+ saves 8%, 4+ saves 12%, and 5+ saves 15% off the whole system, applied at checkout.

Alkalinity
Calcium
Jebao Doser 3.1 Single Dosing Pump