Brown, deformed leaves

Magnesium deficiency and damage caused by wetting the leaves when watering manually.

It looks a lot like Phosphorus issue which is likely due to a pH issue. Here is something i copied and i'll paste it here for you to read Solution For Cannabis Phosphorus Deficiency 1.) Adjust pH to Correct Range Your cannabis plant may show signs of a phosphorus deficiency if the pH at the roots is not in the right range. That is because when the pH of your root zone is off, your cannabis cannot properly absorb phosphorus through its roots. Therefore the first step is to ensure that you have the correct pH for your growth medium. Learn more about pH and cannabis. Phosphorus is best absorbed by cannabis in soil at a root pH of 6.2 – 7.0. Phosphorus is best absorbed by cannabis in hydro at a root pH of 5.5 – 6.2. If you believe you have a cannabis phosphorus deficiency, it’s important to check the pH of your root zone to make sure the deficiency isn’t caused by the pH being too high or too low. If you suspect your growing cannabis plant has a phosphorus deficiency, flush your system with clean, pH’d water that contains a regular dose of cannabis-friendly nutrients that includes phosphorus. This will remove any nutrient salts that may be affected the uptake of phosphorus and help restore pH to the proper levels. In soil, phosphorus is best absorbed by the roots in the 6.2 – 7.0 pH range (in soil, it’s generally recommended to keep the pH between 6.0 – 7.0, but phosphorus specifically tends to be best absorbed above 6.2 and below 7.0) In hydro, phosphorus is best absorbed by the roots in the 5.5 – 6.2 pH range (in hydro, it’s generally recommended to keep the pH between 5.5 – 6.5, but phosphorus specifically tends to be best absorbed below 6.2)

Definitely need to introduce calmag to your line up,no more frequently than once a week. Also check your run off ph, to see what's happening with the substrate. Goodluck.

I would say calmag and ph issues. Check runoff ppms to see if your deficient or toxic. This will let you know immediately if your low or high. I would guess low. Check those ppms and ph in the runoff. Magnesium (Mg) deficiency: a classic magnesium deficiency symptom is leaves yellowing between the veins, while the veins remain green. Irregular yellow-brown spots may appear on older leaves, and eventually lower leaves curl and drop. Sulfur (S) deficiency: young leaves turn yellow and plants become short and small.