The yellow leaves with green veins points to a micro
nutrient deficiency, either Zinc, Manganese or Iron (if those are young leaves). A calcium deficiency would be tip burn and/or brown spots.
The leaf curl is pretty common depending on the cultivar, and it isn't a serious problem.
Maybe leach the solution and try some CalMag?
I had the same symptoms briefly on my tomato plants but it went away after a res change. I think it was an iron deficiency from my pH being off.