failures

alright so i tried a couple batches in the ag classic the plants started to grow then starting getting burns and turning yellow and growth pretty much slowed down to a hault I keep cleaning my res and still the plants just end up sprouting then the symptoms start happening. Im using no nutes at the moment just tap water and it seems like the very tip of the tap root when it starts growing into the water gets fat. anyone have a clue of what im doing wrong.

thats your problem, tap water, the PH is probably really high, you have to research a lil, i dont get how people just jump into thing with out knowing what to do