Nitrogen toxicity curving leaf tips

My soil is 50% vermiculite 50% substrate, it has an excellent drainage always water until water comes out at the bottom, usually I put 2l of water and about 500ml comes out at the bottom of the pot, there was no way to measure the pH so I did a 20l watering filtered water. They weren't getting dense buds so I reduced the watering leaving two days without watering as they are on the billboard, two days without watering is too much.

Thing you need to do flush it then let the soil dry well and water it with an organic N nutrients or just half dose of you favorite nitrogen nutrients add cal mag, get a nice good ventilation, probably the leaves would not go back on its normal stage but it will stop back on getting worst,

Flush to remove excess nutes, you can use any water you like as long as you have the ph set for flower. Or if you dont think it's to overnuted then just water until levels lower. Those spots on your girls are from not enough water to runoff. Your leaving dry areas in your roots, that causes those spots. Cheers