You don't have a diary and it's hard to tell from just one picture - but it's not a calcium deficiency I'm seeing... more like heat stress (leaf edges curling up) and maybe the start of a postassium deficiency - but can't say for sure. Better if you'd start a diary and give us all the information you can about this grow - even if you can only reconstruct the last week or two... We don't even know what it is you're growing!
Good luck