Looks like heat stress. Cupping leaves, crunchy tips...
Could also be nute burn, you're already at 1100ppms which can be high. If you're ppms increase as the water level decreases, you're over feeding.
Your pH is a bit high. I'm assuming you're using hydro, so go down to 6.3. This can lockout certain nutes and give you deficiencies.
Last possibility is a calmag deficiency.