Well it seemed like a good time to refresh the nutrient. If you leave nutrient in a system and just replace water and top off the nutrient if there is any imbalance it tends to increase and ultimately cause problems for the plants. So this morning I went out and swapped a lot of the nutrient by pumping it out of the pond and dumping it on the garden which has not been fertilized.
I pumped 3 and a half buckets out before replacing it with fresh water and topping the nutrient off with 2 and a half cups of concentrate. That brought the CF to 22 but it was not in equilibrium so I'll check it later. Mission accomplished. The frames are working fairly well to sequence the plants off the float so that the support is divided. I don't want the floats to submerge although so far they seem pretty good. These tomato plants are doing markedly better than those in the garden.