When to turn up lights

Before Flowering in my opinion. like after 3 weeks they can start to take a lot of light.. Turning up the light now will probably cause a negative or adverse reaction. So be prepared for that if/when you decide to. When the amount of photons increase the amount of transpiration and intake increases.. You already seem to be having a few nutrient issues and cranking the light up will only give you more issues. But that being said Light is one of the most important things for cannabis growing.it has the biggest impact on yield. It's always better to have plants grow into light and to gradually increase things then it is drop the light 6 inches or crank the light up 25%.. 100% power 24 inch height is what I'd be doing with those lights but I am in hydro.. And Transpiration is a huge part of plant biology and Water is required for transpiration.