The last few days I had 3 plants start not looking...

Hello ! After I check you ec/ppm level I can't really say that you've using an aggressive nuts schedule as 1.3 Ec is good for 34 days old vegings plants, if you give them plain water every 3 watering then it is perfect and if not then flush your medium just a bit. I bet your issue is mostly due to the tap water vs distilled water: which one is leading to the issue ? I would bet on the distilled water as the level of cal mag is 0 in it. I bet you've got a cal mag issue leading to others deficiencies. Concerning your PH fluctuation I can't actually tell you why your PH is rising but I can tell you that coco is a bad buffer so it can make Ec change while the plant are sucking nutrients , in my case (Blue dream) the Ec was going down every time until I start using organics nuts. PS : I know that Ghe floraseries often making PH rise in hydro so I bet the same is happening to you in coco. Hope it will help you 😁👍