Purple punch and Ice cream cake

This week I added CO2 to the garden. My pH in the DWC dipped to 4.6 which was scary. I knew something was wrong bc usually I'm adding water every 36 hours and it was still alot left. I adjusted it to 6.1 and hopefully she recovers...I must say the dwc is so sensitive compared to soil..good grief. During week 4 they only got hit with nutes once then water throughout the rest of week. Update: I decided to drain the dwc and just put in 1gal of water at 5.8 pH. I'm being extra cautious since it's up in the air if the issue is light burn or nutrient deficiencies. Update: Two days before the end of week 5. The purple punch is doing great so far..glad I took cuts. Ice cream cake is absorbing nutrients but the pH is still dipping to the 4s almost every 6 to 8 hrs. I'm just going to keep adjusting the pH and keep her rolling.