I can't say for certain that I observed a KNO3 deficiency. It may be that N and traces go hand in hand. So far it's working and I'm kind of relieved to get PO4 out of the picture for now.

The only reason I went for the Kent trace mix is because I'm the newbie here I would rather dose light and observe after 24 hours. Increase or decrease as needed.

KNO3 is at 2ppm every two days. I'm slowly reaching a target of around 5pmm with a max of 10ppm. I've not tested for more than a few days so I'll have to do that tonight and see how much my uptake is changing. The caulerpa can get quite weedy.