High Moznurseuk,
The spots on your leaves are caused by calmag dificiency. You need to add some calmag with your nutritions.
Also make sure that the pH of your water is right. You can measure the pH of your water and nutrition solution and this should be close to 6.2 on soil.
You can also measure the pH of your soil using demineralized water. I always do this just to check if my soil is still in the right pH range. This is really easy and can be very helpful.
You need a measure cup of at least 250 ml. Then you add 150 ml demineralized water and you add soil till you reach 250 ml. Let it solve and stir well for a minute. After this you can use your pH meter to check the pH from your soil.
Happy Growing! 😋