What can I do for the color problem on the leaves?

You don't typically water till runoff when growing in soil, will drown the plants root system unless its heavily amended with perlite. not ideal. you can go down to a PH of 6.2 with BioBizz Nutrients in soil as well. Its best to let it sit out for 12hrs before adjusting PH as it drifts over the course of that time. It would also be in your best interest to invest in a TDS/EC Pen, when using liquid nutrients its a great reference point to confirm your feeding concentrations and troubleshoot any issues. Good Luck!

They are showing magnesium deficiency and I believe your feeding too strong causing nute burn on tips and locking out nutrition like magnesium. If you are not getting adequate run off each feed then you have a salt build up from old nutrition not washing out as you put in new. Which will cause major issues soon. Would be my observation from looking at plants and your diary.