Recommended calcium supplements?

[Jayfar]

Originally Posted by tucker85

I agree. I think the most important thing is that these products are chelated minerals which are more readily available to the orchid and that the magnesium and calcium are used together. I've read that they're absorbed better when used together.

Well, for the metals anyway, i.e. the chelated Iron.

Chelation - Wikipedia, the free encyclopedia

Fertilizers
Metal chelate compounds are common components of fertilizers to provide micronutrients. These micronutrients (manganese, iron, zinc, copper - are required for the overall health of the plants. Most fertilizers contain phosphate salts that, in the absence of chelating agents, typically convert these metal ions into insoluble solids that are of no nutritional value to the plants. EDTA is the typical chelating agent for this purpose.