- Ships in 7-10 days.
Aquarium and pond equipment at the best prices!
For those passionate about aquariophily
Having trouble finalizing your order? Contact us 24 hours a day by email at information@zoanthus.fr.
Basin Analysis
5€ discount for your first order with the code: BIENVENUE05 (from 100€ purchase, offers cannot be combined)
Balling Products
Seawater supplements
Basic elements
Fresh Water Supplements
CO2 system
5€ discount for your first order with the code: BIENVENUE05 (from 100€ purchase, offers cannot be combined)
Water treatment
Bacterial Treatments
Adverse Treatments
Fish Care
Water treatment
Bacterial Treatments
Adverse Treatments
Fish Care
Water treatment
Bacterial Treatments
Fish Care
5€ discount for your first order with the code: BIENVENUE05 (from 100€ purchase, offers cannot be combined)
5€ discount for your first order with the code: BIENVENUE05 (from 100€ purchase, offers cannot be combined)
Sand
Substrate for reactor
Sea Salts
Pond Substrate
5€ discount for your first order with the code: BIENVENUE05 (from 100€ purchase, offers cannot be combined)
Seawater Equipment
Basin Equipment
5€ discount for your first order with the code: BIENVENUE05 (from 100€ purchase, offers cannot be combined)


Magnesium + Zoanthus Lab 1000 ml is a concentrated solution designed to precisely correct magnesium deficiencies in marine aquariums. Essential for the chemical stability of seawater, magnesium (Mg) contributes to overall ionic balance and helps maintain a proper ratio of calcium, KH, and salinity. Formulated with purified water , pharmaceutical-grade magnesium chloride hexahydrate , and pharmaceutical-grade magnesium sulfate heptahydrate , this product guarantees a clear, stable, and perfectly measurable concentration. Free of unnecessary additives and complexing agents, it integrates perfectly into a rigorous management system based on ICP analysis. A reliable, transparent solution designed for discerning aquarists.
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Zoanthus Lab Calcium 1000 ml is a concentrated solution designed to precisely correct calcium deficiencies in marine aquariums. A central element in reef balance, calcium (Ca) is essential for the growth of hard corals, giant clams, calcareous algae, and many other reef-building organisms. Formulated with purified water and pharmaceutical-grade calcium chloride dihydrate , this supplement offers a clear, stable, and perfectly measurable concentration. Free from unnecessary additives and complexing agents, it integrates seamlessly into a rigorous management system based on ICP analysis. A reliable, transparent solution designed for discerning aquarists.


KH + Zoanthus Lab 1000 ml is a concentrated solution designed to precisely correct alkalinity in marine aquariums. KH is a fundamental parameter for reef balance, directly linked to pH stability and the proper functioning of calcification processes in hard corals, calcareous algae, and other reef-building organisms. Formulated with purified water , pharmaceutical-grade sodium carbonate , and pharmaceutical-grade sodium bicarbonate , this product guarantees a clear, stable, and perfectly measurable solution. Free of unnecessary additives, it is ideally suited for rigorous management based on ICP analysis. A reliable, transparent solution designed for discerning aquarists.
Magnesium is a major element naturally present in seawater , generally at a concentration of around 1280 to 1350 mg/L. It plays an essential role in the overall stability of the reef tank, notably by helping to maintain a good balance between calcium and alkalinity.
In a marine aquarium, magnesium indirectly supports calcification processes by limiting certain undesirable calcium precipitation. A consistent level therefore promotes better chemical stability, particularly in reef tanks heavily populated with hard corals and other calcifying organisms.
We offer a full range of products to target the main elements of seawater following ICP analysis or manual testing.

The Zoanthus Lab – Magnesium +/- solution is prepared from magnesium chloride hexahydrate (MgCl 2 ·6H 2 O) and magnesium sulfate heptahydrate (MgSO 4 ·7H 2 O) , dissolved in purified water.
This combination provides magnesium in a balanced form, tailored for precise reef supplementation. The use of pharmaceutical-grade raw materials ensures a clean, stable, and consistent solution, supported by rigorous monitoring through ICP analysis.
The solution is formulated according to a precise protocol:
Supplementation should always be based on a recent ICP analysis or reliable measurements. In case of a marked deficiency, it is advisable to spread the correction over several days to preserve the ionic stability of {index=1} tank [oaicite:1] avoid overly abrupt adjustments.
Each Zoanthus Lab product can be controlled via our free Zoa Aqua Manager calculator. In just a few seconds, you get a precise and personalized dosage from your ICP analysis (Zoanthus Labs or any other laboratory).
No more manual calculations: enter your water volume, your measured value and your objective, and the system automatically calculates the appropriate correction, with the possibility of progressive dosing for optimal stability.
A tool designed by aquarists, for demanding aquarists.

The essentials for reef aquariums
Complete analysis of the major elements and trace elements essential for the regular monitoring of your reef aquarium.
Ultra-comprehensive diagnosis
In-depth reading with expanded spectrum including fluoride, nitrates, KH and reverse osmosis water analysis.
Special reverse osmosis water
Precise control of your preparation water to ensure a perfectly healthy base before any remineralization.
The results of each analysis can be directly used in our free Zoa Aqua Manager calculator for precise and personalized dosing.

Add to a well-circulated area of the aquarium or to the sump. Shake well before use.
Store away from light, between 15 and 25 °C, in a tightly sealed container. The protocol also indicates that storage in [oaicite:2] airtight and opaque container is recommended to preserve the {index=2} of the solution.
As with any major element, excessive supplementation is unnecessary and can unbalance the water. Regular monitoring via ICP analysis remains the most reliable method for maintaining a stable tank in the long term.