DarkWizard021 the rate of death you described sounds like disease. The only other situation I can think of is water temps bordering on being completely anaerobic and likely exasperated by root rot. Although, it looks like you possibly didn't use enough hydrotron to block the light. If light gets in the roots will be slimed to death, or suffer from rot. The most common to aero/hydro/water is root rot from excess reservoir water temp as I already mentioned. You can possibly get through it at 72F using Hydroguard but 65F is really ideal it has a great amount of oxygen and personally I like 60F best, a temp most people say not to run at. I've ran 55F water with great results also when my floors are cold I don't put a heater down until the water goes under 55F, at which point I feel like the plants stall a little. I honestly wouldn't invest a penny in my grow if I couldn't keep the water temps below 70F I do not think that is any advantage to soil.
(edit: water temps above are for aero, roots hang in the air and are sprayed by water one minute out of every 6)
Sorry to see sudden plant death it is the worst feeling in the world but just bleach everything out and reset. I've grown in hydro for years but I am switching to organic soil water only now, the opposite of what you did, kind of funny. Here's a thread I did on mixing your own nutrients which personally I find to be an incredible hard to foul system of growing in aero.
https://www.rollitup.org/t/hydrobuddy-free-hydroponic-nute-calc-by-chem-scientist-botanist-mix-own-nutrients.368514/
really sad to see your loss