If your going to pop them outside when the temps warm up then keep topping them and getting as many new nodes growing as possible, you'll be well rewarded with extremely bushy plants with a ton of colas
Online it shows as $1520 for 100 pounds. When I worked it out, the per liter price with shine and life it worked out to a little over 5-6c a liter following their formula. For many of the other nutrient companies it comes out to 2-3c a liter.
I think the yields on LED has improved rapidly but the costs are still prohibitive. From the calculations I've seen you don't really start to see the savings till the end of the second year.
I've been reading up on them and a lot of people are using it and loving the results. About my only complaint is the retail price from the site makes it two to three times more expensive then many other nutrients
Have you been checking the ph of what you are feeding your plants and what the runoff is? Looks like a ph problem to me but testing would tell you that
The light makes it a little difficult but the way it seems to effect the edges a lot more makes me suspect nute burn. Did you try a flush and check the ppm of the runoff?
First time I used DWC and they stayed healthy for over a year and half but it was a lot of maintenance as we kept only 2 mothers each of six strains and they all seemed to like a slightly different mix of nutrient. Second go we went coco and it was just a hell of a lot easier in big 10 gallon...
My last few grows I've used Rockwool only as the starter and then inserted them into hydroton. Was thinking of doing the same into coco but just growing in bigger cubes looks interesting. Do you have any worries about over saturation and what are those outside plastic cubes you have them in?