Very Low Watt Εxperiment

On day 28 i stop nutrients and i did a flushing to the plant because the soil has much more nutrients (On the next grow maybe i use biobizz light mix soil or i try for the first time an hydroponic DWC system) ... On day 33 i did a flushing again , my plant is very sick with nutrient burn or disease from thrips , maybe i use a very bad soil ... My plant growing very very slow ... Is this on day 32 nutrient burn or disease from thrips ???