Athena Cal Mag – 5 gal

Athena Cal Mag in a 5-gallon jug is the bulk pack of Athena’s calcium-magnesium supplement. CaMg corrects calcium, magnesium, iron, and nitrogen deficiencies during heavy growth and bloom, without throwing off the overall elemental balance of a Athena 2-part program. The 5-gallon size is sized for multi-tent home grows and small commercial canopies that consume more than a quart of CaMg per month.

Athena Cal Mag 5-Gallon Specifications

Athena Cal Mag (sometimes labeled CaMg) is a clean calcium-magnesium-iron-nitrogen supplement designed to slot into Athena’s Pro and Blended liquid programs. The 5-gallon jug is the largest single-jug pack Athena offers for CaMg and is the standard re-order size for small commercial operations and multi-tent home grows.

Why Choose Athena Cal Mag

CaMg is positioned as the calcium-magnesium corrective leg of Athena’s Blended (liquid) program rather than a standalone bloom booster or root-zone stimulant. The reasons growers running an Athena program standardize on CaMg in the 5-gallon size:

• Built around the Athena Blended line. CaMg is formulated to stack on top of Athena Grow A/B or Bloom A/B without precipitate, EC spike, or pH drift. If you are already feeding the Blended 2-part, CaMg slots in without recalculating the rest of the program.
• Targets the four nutrients most likely to short. Athena’s stated function for CaMg is correcting calcium, magnesium, iron, and nitrogen deficiencies. Those are the four elements that most often run short on RO water and in inert media, in that order.
• Clean elemental balance. CaMg is formulated to correct deficiencies without throwing off the rest of the elemental ratios that Athena’s base nutrients deliver. It is not a kitchen-sink supplement.
• RO and inert-media focus. Operations on RO water and growing in coco or rockwool give up the calcium and magnesium that tap-water carbonates and peat-based mixes contribute on their own. CaMg replaces that baseline without forcing you off RO or off coco.
• 5-gallon pack economics. Stepping up from quart or gallon bottles to a 5-gallon jug eliminates the per-gallon packaging premium and stretches re-order cadence for small commercial operations.
• Same SKU at every pack size. Athena CaMg is the same formulation at quart, gallon, and 5-gallon size. The 5-gallon jug is the bulk version of the same product Athena sells in the smaller jugs.

Best Uses for Athena Cal Mag 5-Gallon

The 5-gallon jug is sized for grows that move through CaMg in volume but do not yet need drum-scale packaging:

• Multi-tent home grows. Operations running multiple tents off a shared reservoir and fertigation loop draw from one jug across the entire feed program rather than juggling several smaller bottles.
• Small commercial canopies on RO. Single-room and few-room commercial operations on RO water typically dose CaMg at every feed; the 5-gallon size matches that consumption pattern without the storage burden of a drum.
• Coco and rockwool programs. Inert media gives the grower full control of the calcium and magnesium baseline. CaMg provides that baseline at a known concentration without contaminating the recipe with other minor or accessory nutrients.
• Crops showing intermittent deficiency. Heavy-feeding cultivars and high-light environments push calcium and magnesium demand above what a 2-part program delivers at standard rates. CaMg is the corrective lever.
• Mother and clone rooms. Heavy-throughput mother stock and clone propagation under high light pulls calcium and magnesium hard during early establishment; CaMg holds the baseline steady.
• Backup against feed schedule drift. Even on tap water, mineral content drifts with the season. A 5-gallon jug of CaMg is the operator’s standard correction tool when a leaf-tissue or runoff reading shows Ca or Mg drift.

If your grow is below the threshold where a 5-gallon jug pencils out, our Athena Cal Mag 1-gallon is the same product at a single-tent or single-room pack size and runs the same 2.5 mL per gallon application rate.

Athena Cal Mag 5-Gallon vs Smaller Pack Sizes

Athena publishes CaMg in several pack sizes from quart up through this 5-gallon jug. The formula is the same across pack sizes; the choice is a question of throughput, storage, and cash-flow rather than chemistry:

If your operation is consuming less than a quart of CaMg per month, the 1-gallon pack is the right starting point; the 5-gallon jug ties up capital and shelf space without paying back the per-mL savings. Above roughly a quart per month, the per-mL economics flip and the 5-gallon size becomes the cheaper option.

Compatibility & Operating Range

CaMg is designed to slot into the Athena Blended (liquid) feed program. The compatibility envelope is published by the manufacturer:

• Compatible nutrients: Athena Grow A/B and Bloom A/B base nutrients, the rest of the Athena Blended catalog (PK, Bloom Boost, Cleanse, IPM), and Athena Pro (dry) when run as a hybrid Pro plus Blended program. CaMg is also tolerant of most third-party base nutrients but you should run a small reservoir test before mixing into a production tank.
• Application methods: reservoir dosing or hand-watered drench. The 2.5 mL per gallon rate is low enough to deliver cleanly with a small syringe at a hand-watered scale or with a metering pump at a fertigation scale.
• Crop compatibility: Athena publishes feed schedules for indoor and greenhouse cultivation, soil and inert media. CaMg applies across those scenarios. The dose rate is the same; the frequency varies by media, water source, and crop stage.
• Storage: store the jug in a temperature-controlled space between 45°F and 85°F. Avoid freezing and direct sunlight. Keep the cap sealed when not actively drawing from the jug.
• Mixing order: follow the Athena feed schedule for order of operations. CaMg is typically added after base nutrients and before adjusting pH. Adjust pH only after every additive, including CaMg, is in the mix tank.
• Service life: at 2.5 mL per gallon, a 5-gallon jug treats roughly 7,500 gallons of feed water. That covers many months of feeding for a small commercial canopy or multi-tent home grow.

For operators stacking calcium-magnesium with a dry-format base program, our Athena Pro Core 25 lb is the dry base nutrient that pairs with CaMg in a Pro plus Blended hybrid; verify EC and pH behavior in a mix tank before plumbing it into shared fertigation.

Usage & Dosing Guidelines

Athena publishes a complete feed schedule covering the Blended program, including CaMg. Refer to the current Athena feed chart for the exact ml-per-gallon rate by crop and growth stage; the manufacturer recommendation for CaMg is 2.5 mL per gallon of water across all stages as needed:

• RO and low-mineral water: dose at the full 2.5 mL per gallon rate at every feed. RO and rain water carry virtually no calcium or magnesium baseline; CaMg supplies that baseline plus the corrective margin.
• Tap water and well water: verify source-water EC and Ca/Mg content before dosing. Many municipal supplies already deliver 50 to 150 ppm Ca and 10 to 30 ppm Mg; CaMg adds on top of that baseline and you may run a reduced dose to avoid stacking calcium past target EC.
• Coco and rockwool: coco in particular binds calcium and magnesium during the first wettings. Dose CaMg through the full grow cycle on coco; on rockwool the dose is steady from veg through bloom.
• Deficiency response: visible calcium deficiency (interveinal chlorosis on new growth, tip burn) and magnesium deficiency (interveinal chlorosis on older fan leaves) both respond to CaMg correction over the next one to two feeds. Long-standing deficiency may require a stronger short-term correction; consult the Athena feed chart for stress dosing.
• EC management: CaMg contributes a documented amount to total EC. Adjust other Athena Blended line products against the published schedule to stay within target EC for the crop and stage; do not stack additives without recalculating EC.
• pH adjustment: add CaMg before pH adjustment. The product is mildly buffered, so adding it after pH is set will require a re-check and re-adjustment.

How to Set Up the 5-Gallon Jug

Integrating the 5-gallon jug into a reservoir or fertigation setup:

1. Inspect on arrival. Check the jug for shipping damage, then check the cap seal and the tamper band. CaMg is a clean liquid; any visible discoloration on the outside of the jug warrants a closer look at the cap before opening.
2. Position the jug. Place it in a temperature-controlled space between 45°F and 85°F, ideally near the reservoir or central mixing station. Avoid direct sunlight and the floor area immediately under HVAC drops where temperature swings are widest.
3. Choose a dispensing method. For hand-watered grows, decant from the jug into a smaller mixing bottle for easier daily handling. For fertigation, install a drop-in pickup tube into the jug and run it to the injector.
4. Calibrate the dose. Set the dispensing tool (syringe, measuring cup, or injector) against the 2.5 mL per gallon rate or the current Athena feed schedule for your crop and stage. Verify the actual delivered ml-per-gallon with a measured catch test at a sample emitter or by weighing a test pour.
5. Add to the mix tank before pH. Add base nutrients first, then CaMg, then any other additives, then adjust pH last. CaMg has mild buffering that will shift a pre-set pH if added afterward.
6. Shake the jug periodically. CaMg is a clear, low-viscosity liquid but should be shaken gently before drawing a new dose if the jug has been sitting unused for more than a few weeks.
7. Test on a small section. If you are introducing CaMg into an existing feed program, deliver it to a small test block first and confirm the EC and runoff response over two to three feeds before rolling out across the canopy.
8. Log the open date. Track the jug’s open date and weekly consumption rate to schedule re-orders before you run dry. CaMg has a long shelf life in a sealed jug; once opened, plan to use the full 5 gallons within roughly 12 to 18 months for best results.

Sources & Further Reading