crop tastes bitter

[Rockwool]

Thanks to advice found here everything in my ebb and flow system is growing great! One problem though is that some of the
crop tastes bitter. The arugala is too bitter to eat and the thai lemon basil is as well. Broadleaf basil is not as bad but not very
tasty. The garden is run with a well controlled set of parameters except that I stopped checking pH daily but get to it at least
weekly. I am using Rockwool and the formula 1 A+B mix. Any advice?