Why is everything dying?

The problem was the soil. Canna terra professional. This is only good for the first 7 days apparently. Switched to biobizz allmix, and whatever was left, is turning green.

If you think you might be over watering get some fabric pots. They make it VERY hard to over water, but you will have to water more often because the evaporation rate will go way up.

I'd get rid of the domes and check water amount and quality. This could be from overwatering, how much were you using? What's your room temperature and RH?

Thanks for the responses! The first picture is an Auto Gelato, top half of the pot is filled with Canna Terra Professional (not plus), and bottom half with BioBizz Allmix. Second picture is an Auto Amnesia, same stuff in the pot as the first one. So far only ph water given, 6.3-ish. I use good genetics, Barneys, Greenhouse, Sweet Seeds (spain). I have no idea about the EC and PPM. I water small amounts twice a week, definitely not overwatering. I'll also make a growreport here! Seems like one of the better websites! Oh, temperature is at 26 degrees celcius stable, mars hydro tsw2000, about 300 watts. I have it at 30inches, which is around 8pcm i think, at 60÷ power.

Best start with all your grow details. Auto or photo? type of soil, any amendments type of nutrients, and amounts you're feeding. Water source, PPM/EC details on pH. what lights, what wattages (actual not advertised), how high, what schedule? If you have PPFD numbers that helps. What is the feed/water schedule what is the temp/RH?

Picture 1 looks like potassium deficiency, picture 2 looks fine, and picture 3, if those are not clones, I wouldn't have them under a dome for humidity.