Big Bud in DWC

This girl is already 2 weeks old 🎉I have several problems with the water quality tho, I don't have capacity to use distilled or RO water, so I use dechlorinated tap water which is the main reason of PH drifting upwards. I have to use PH DOWN in every 24 hours. It's not a big pain in ass such as the temperature, sometimes it reaches 27 celsius (80F). I have to solve the problem before the roots reach the water, I put a 1 Liter frozen water bottle and after monitoring it, the temperature went down to 23 celsius (73F) after 2 hours, I don't know how long will the water maintain that temperature but it's obvious the method isn't going to work for a long time, I'm thinking about raising the lights height up a bit in one or two days. I'll set it from 45cm to 60-65 cm.