Test Kit: Magnesium
G2870
The Waterbox Magnesium Test Kit offers fast, reliable testing to determine the magnesium (Mg) concentration in saltwater aquariums. Magnesium is a core element in reef chemistry, supporting coral skeletal growth...
Or build it into a bundle — save up to 6% ↓What it is, and who it is for.
The Waterbox Magnesium Test Kit offers fast, reliable testing to determine the magnesium (Mg) concentration in saltwater aquariums. Magnesium is a core element in reef chemistry, supporting coral skeletal growth and helping maintain overall stability in the system. It plays a major role in balancing calcium and alkalinity, and its presence helps reduce unwanted calcium carbonate deposits on pumps, heaters, and other equipment.
Consistently maintaining magnesium within the natural seawater range of 1200–1400 ppm is essential for healthy coral development and for keeping other key parameters in check. Regular testing alongside alkalinity and calcium helps maintain a balanced and thriving environment.
Each kit provides enough reagents for roughly 55–60 individual tests.
Build around the Test Kit: Magnesium.
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 test kits. Most buyers reading this page should buy the middle column.
Test Kit: Calcium
Test Kit: Magnesium
JBL ProAquaTest Freshwater Test SetAsked 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.