Brown and Yellow leaves! Please help

Fellow growers PLease let me know what is wrong with my plant. This is my first hydro grow. Ph is good at 6.0 reservoir temp good nutrients at 1.6 ec RH at 45

I believe it is a mag def is that correct? would cal-mag clear it up. Can it be saved?

Thanks
Nick

can't see much of the newer growth but what little i see tells me you're past that problem. maybe a little nute burn in the beginning.
get a good balance fertilizer. looks like a little magnesium and nitrogen deficiency. GL