Plants don't eat much the first couple weeks of flower; as you can see with your EC and PH. Topping off the reservoir daily is required to replace the missing fluid and help keep the PH and EC in proper range.
Pro-Tek or other Silica additives are also useful to help stabilize the PH. I consider it a must for any feeding schedule. Search the website for Pro-Tek; I know there's a good article about it. Let me know if you have any questions.
[Hint] Pro-Tek MUST be added to your reservoir first before any other nutrient is added. Adding it after your nutrients will have a negative effect and lock-up.
How big is your reservoir?
tttttPH swings typically down can also be an indication of a bad bacteria infestation. How do the roots look?
Is that ph and ec before or after a top off?
this is from a growers guide on dutchmasters website. Ive found it to be pretty true to my own personal experiences:
"Generally the pH of a solution tends to rise during the grow cycle ( as the plants take up more nitrogen which causes the pH to rise ) and to fall during flowering when the plant has a preferential draw on Phosphorus. "
If your only topping up twice a week your ladies are probably drinking more water and leaving the nutrients behind especially when they fall out of the ideal ph range causing your ec to rise.