calcium and magnesium supplements

[utah]

I recently purchased some ground oyster shells for calcium supplementation for my paphs and was wondering if there are other orchids which would benefit from added calcium.

Same question regarding magnesium (Epsom Salts) diluted in water. I've used it to help orchids with yellowing leaves but wonder if there is any additional need for magnesium as a supplement and which orchids could use the supplementation.



Thanks

Utah