Fixing calcium & magnesium deficiencies

Two secondary nutrients, two jobs

Magnesium forms the centre of chlorophyll. Calcium supports cell wall strength. Monkey Mag Cal supplies both secondary nutrients with trace elements. The product is particularly relevant to soft water, reverse-osmosis water and coco growing. Those use cases explain why the bottle exists; they do not establish a diagnosis from a photograph. If a plant looks unhealthy, record the medium, water source, current programme and recent changes before assuming a single nutrient is missing. Several variables can look similar when all you see is a damaged leaf.

Why coco changes the conversation

Coco has high cation exchange capacity and can bind calcium and magnesium. That is why the Monkey feeding chart specifically says to use Mag Cal for coco. A grower moving from soil to coco should not simply copy every previous decision without considering the new medium. Equally, a grower using RO water should make that fact clear when speaking to a stockist. A useful question is not just whether to buy cal mag, but how it fits with the complete base nutrient system, medium and water source already in use.

Confirm the missing dose

A confirmed dose for Mag Cal is not present in the supplied Monkey data. The correct response is to ask your stockist, not borrow a figure from another brand or infer one from bottle size. The nutrient calculator therefore shows confirmed chart products and leaves Mag Cal dosing uncalculated. Keep this distinction clear in your own notes. An accurately measured but unverified recommendation is still unverified. When the brand confirms the missing instruction, it can be added consistently to the product information and schedule.

Check the programme before you start

The Monkey feeding chart is written as a ratio per 10 litres of water. Its headings distinguish vegetative growth, bloom and flush, and the programme toggle selects PK or Resin. Before measuring anything, check that the week on the screen is the week you intended. A veg week and a bloom week can share a number but involve different base feeds. The chart’s ranges should remain ranges in your notes. A displayed interval does not mean that the website has secretly chosen one precise value for your crop. Read the full row and the surrounding programme rather than lifting a number out of context.

The calculator is a convenient way to change reservoir volume without changing the underlying chart. Enter litres, choose the week and programme, and read the millilitres for each included product. If you double the water volume, the confirmed amounts double; if you halve it, they halve. A product without a confirmed dose is not automatically assigned one. This simple boundary is important: arithmetic can scale an instruction, but it cannot supply missing product guidance.