Aptus MINERAL-CALMAG, 5 L

Buffer Your Feed Water and Prevent Ca-Mg Deficiencies in Soil-Less Systems

Soil-less growing mediums — coco coir, perlite, rockwool, hydroton — offer precise control over the root environment, but that control comes at a cost: the medium provides no natural mineral buffering and often strips calcium and magnesium from the feed solution before the plant can access them.

Mineral-CalMag is a 100% water-soluble calcium, magnesium, and nitrogen supplement formulated to prevent Ca-Mg deficiencies while also stabilizing feed water pH — which makes it particularly well-suited to recirculating systems, fertigation setups, and longer reservoir holds where pH drift can compound over time.

Dosage scales with water source: filtered or RO water requires more Ca-Mg buffering than municipal water, and the numbers on the label reflect those differences precisely.

Key Features & Benefits

• 100% water-soluble Ca-Mg-N formula — delivers calcium, magnesium, and nitrogen in fully plant-available forms without residue or precipitate.
• pH stabilizing capability — buffers feed water to prevent the pH drift common in recirculating and fertigation systems over extended reservoir holds.
• Prevents Ca-Mg deficiencies in soil-less media — formulated specifically for coco, perlite, rockwool, hydroton, and recirculating hydroponic systems.
• Scales with water source — dosage adjusts from 1.5 ml/gal with a 2-part NPK up to 3–4 ml/gal with RO or soft water, matching the buffering demand of the actual water being used.
• Preferred CalMag for fertigation systems — chosen by commercial cultivators running fertigation and recirculating systems for its stability and pH performance.
• Sized from 1 to 20 liters — lets growers match the bottle to the reservoir volume and dosing frequency of their system.

Who Should Use Aptus Mineral-CalMag

Growers running soil-less systems — coco, perlite, rockwool, or recirculating hydro — who need reliable Ca-Mg supplementation and feed water pH stability, particularly those using RO or soft water or running long reservoir holds where pH drift is a concern; with the 5 L size matched to system scale.

Adjusting Dosage by Water Source

With a 2-part NPK: 1.5 ml per gallon (0.4 ml per liter). With Aptus BASE and municipal water: 2.5 ml per gallon (0.6 ml per liter). With Aptus BASE and RO or soft water: 3–4 ml per gallon (0.8–1 ml per liter). Start at the lower end of the range and adjust based on observed plant response and EC readings.

Frequently Asked Questions

Can Mineral-CalMag be used as the sole calcium source alongside Aptus Liquid Base?

Yes — it's one of the two approved Ca sources for Liquid Base (the other being Massboost). It can be used throughout both vegetative and flowering stages as a continuous Ca-Mg supplement.

Why does dosage change depending on the water source?

RO and soft water contain fewer dissolved minerals, which means the feed solution needs more buffering from Mineral-CalMag to provide stable Ca and Mg levels. Municipal water already contains some calcium and magnesium hardness, so a lower dose is appropriate.

How does Mineral-CalMag stabilize pH?

Its dissolved mineral profile buffers the pH of the feed solution, reducing drift over time — particularly valuable in recirculating and fertigation systems where the reservoir can shift pH between top-offs.

Is Mineral-CalMag suitable for long reservoir holds and fertigation systems?

Yes — it was specifically formulated with these use cases in mind. Its pH-stabilizing properties make it the CalMag of choice for commercial growers running fertigation or recirculating systems with longer reservoir intervals.