A couple of questions...

[Steve_1111]

Hello. I am a pretty new orchid grower/collector and am brand new to Orchidboard.
There are a couple of questions I have that I can't seem to find answers to through Google.
Everywhere lists eggshells and oyster shells as good natural calcium sources (and yes I know it is debatable whether or not added calcium is needed and which plants may or may not...) my question though is: if I wish to add calcium, can I use other seashells? (not just oyster) like say clam, sea snail, etc.

My next question is in regards to Phals and the the induction of flower spikes by lowering the temp. I keep all my orchids in a small greenhouse at about 24 degrees Celsius (day) and 15(ish) degrees (night). Would it induce blooming if I took them out of the greenhouse? It is significantly cooler in the rest of the house. About 10 degrees cooler in the day.

Thank you