PH... and improper use of nutes. That is your problem.

FoxFarms employed an army of scientists to figure out that chart which you have ignored, thinking that you had a better way... now your plants are showing you the result of your miscalculation. I have NEVER measured my run off PH on my soil... I simply don't care what it looks like. I know that if I put the proper ph in, all is well. Follow the chart, and give the proper nutes at the recommended levels only every other time, and properly PH'ed water to 6.45 in-between.

When you add the nutes to your water, especially when you use one of the 3 FoxFarms Solubles, the PH will probably go very low... 5.75 or so. Use PH up or pickling lime or whatever makes you happy, and bring that PH back up to 6.45 before you apply the soup to your plants. The soil is simply the medium this all is sitting in... make sure that what you put in there is what the plants can use, without counting on the soil to change it. 6.45 PH. I am convinced this will solve your problems. Stop worrying about the run off PH. Every soil out there will give you a different result after filtering your nutes and water through it, and each soil will change over time how much it adds or subtracts to the equation. This measurement is mostly meaningless... Just make sure you put the right stuff in.