First Hydro Grow and Lower Leaves Developing brown spots

I am doing my first hydroponics grow with a recirculating DWC system. Originally I added organic nutrients from General Organics Go Box and I had the ppm at 390 and then switched to current culture H2O nutrients since I read organics shouldn’t be used in recirculating systems. I decided to just add current culture h20 nutrients at first and got up to 450 ppm before noticing this issue. I thought it may be a cal deficiency so I added a little cal mag and ppm went up to 500 and the issues seemed to get worse so I diluted my mixture back down to 260 ppm. Up until the dilution Ph was at 5.8 and now it is at 6.0 since dilution and I saw on current culture systems the recommend slightly higher Ph (6.1-6.2) during seedling and vegetative state and also less nutrients when using a recirculating system. I just diluted this morning and not sure it fixed the issue but figured I would get some feedback from the group. I am not at recommended ppm/Ph for current culture recirculating systems.

I don't think it is that uncommon to have the bottom leaves get funky after a transplant. It's adjusting and adapting. I'm not familiar with your nutes but at least you aren't overfeeding and burning them. Since they are still small they can live on light nutes for a little while. If they get hungry they will get lighter and pale looking. You should be able to up the nutes a little in another 10 days or so.