Leaves yellowing and then brown spots and then they finally die..

It started with the lower fan leaves and working its way up it looks like.. N then the very top leaves got little brown rust spots on just the top leaves of my plant... 5 or 6 th week in flower in 5 gal bucket. 250 wAtt mh\hps soil is fox farm ocean and using distilled water with general organics go box nutes bio thrive bloom /calmg+/ bio bud bloom boost and bio marine... I'm a first timer and I don't wana lose my plant can anyone tell me whAts wrong and how to fix....

Salt/Nute build up from over feeding causing lockouts. Flush your medium very well and feed at 1/2 strength.

K thanks how much should I use to flush 5 gal bucket

At least 10 gallons of water. 2x the container size. If you have a TDS meter then you can measure the runoff and around the third gallon or so check it, it should be 100-200 PPM higher than your input water, no more.

EDIT: Don't flood the soil and let it drain, try to add the water at a somewhat constant rate while pouring

Can I use distilled water to flush n the. Use distilled water with nutes after its dries out from flush ?

Here, this guy has the exact same problem, huh...https://www.rollitup.org/newbie-central/697519-leaves-turning-yellow-brown-why.html

Ya that me again I'm new to this site n I thought it got deleted so I did another thread