Hydroponic tomatoes Cambodia
Looks like a Magnesium deficiency, which can be common in greenhouse and container production. Foliar feed your plants some Epsom salt (1 Tablespoon of Epsom salt per gallon of Water). Spray on the leaves until wet one application should show signs of improvement. Be sure to apply again at bloom and fruit set.
OK thank you I will try this. I am growing dwc hydroponics.