pH lock up

I have my plants in my hydro set-up and they are around 3.5 weeks old. I think I might have pH lock up. I usually have the pH at 6 but recently I tried keeping it lower (anywhere from 5.5-5.8) and I've noticed that my plants are not eating any of the nuits. What is a good solution for this?
- even some of the new growth is yellowish and it looks like a nuit deficiency but the nuits went from a EC of .05 at initial transplant and was slowly raised over the weeks to a 1.4 which is where its at now.

You have nutrient burn. Your EC went up after your plants drank alot of water.
Water level goes down nutrient strenght goes up. Top up with PH water and the nutes will be back down.

Change your water and PH it for a couple of days and then add half nutes.