Ok 1.1 going in but qhats coming out? Tip burn like that is not cause for major concern but more of an indicator. Dark green shiney leaves with tips clawing down and tip burn is nitrogen. Excess calcium can also cause this believe it
or not. To add calcium and potassium compete for uptake so thier ratios are important as are all nutrients. I won't get into this but after stretch cut cal mag to half. Ideally calcium doesn't need to be anymore than nitrogen so around 100-150ppm is plenty even when the plants are vigorously growing. Most cal mag calls for double this on the directions. So half dose is about where ya want to be. After stretch can even cut to 1/4 usually without issue.
Potassium demand picks up mid to late flower as N and Ca demands drop. Both can affect K uptake.
So the second last reason you may see tip burn is a K deficiency. It starts usually mid plant and a it progresses it will spread along the edges of the leaves starting to burn the serrations. At that point you know almost for sure its a K deficiency.
light is another cause and will start on the upper most leaves. With K and light tips may start to curl upwards as it progresses.
Now I think this is all cause by fluctuations in the root zone. From concentration to ratio etc. As I posted previously. A flush ir few feeds with high amount of runoff followed by a nutrient dose of probably around 600-800ppm of a balanced nute with half cal mag should help prevent it from progressing.
Lower the light intensity for a few days after and all should be well.
test your runoff to compare what's going in and what's coming out. This is best done with a syringe from the bottom of the pots in the saturation zone if possible but if not just the run off.
can you post the results of that?
