Interesting question tossed up. Under greenhouse , the biggest issue is to cope up with humidity , but checking for pH and EC of water is a challenging task. Dissolving gypsum at 5g per litre of water would probably keep any possibility of salts getting accumulated and harm the plant growth....

Please look at pending file ,i hope this benefit for your request.

We studied the effect of saline water and fertigation on pepper yield in greenhouse in Turkey. Please find the related article in the attached file.

Good question, I'll follow this question

Following