Basil yellowing, curling downward, in deep water culture

[Ng Dong Wei]

Hello fellow aquaponicist/aquaponist:

I was wondering if anyone has experienced the same problem as I had with growing basil plants. This affliction only affects young leaves of older plants and does not seem to affect young transplants.

The basil is grown in the dwc in slotted pots, and the system is approximately 300 gallons. The media bed is about the same size as the runway. My water testing kits have run out and new supplies have not arrived yet. The last things I added prior to incident was a daily 1/2 teaspoons of CaOH, MgSO4, and a few squirts of KOH for about a week. Chelated iron has been added as well. The pH at the time was hovering around 6.6-6.8 at 10-20ppm NO3. The tilapia has been fed with regular fish feed.

What do you think caused it?

Many thanks.

[Art]

Chelated iron helped my basil plants.  I just don't know how much to add or if you need to keep adding.  I am just starting out - only a few months.